diff --git a/icu4c/source/common/charstr.h b/icu4c/source/common/charstr.h
index 175acd1c0a2..92a75d3d2f9 100644
--- a/icu4c/source/common/charstr.h
+++ b/icu4c/source/common/charstr.h
@@ -177,8 +177,8 @@ private:
 
     UBool ensureCapacity(int32_t capacity, int32_t desiredCapacityHint, UErrorCode &errorCode);
 
-    CharString(const CharString &other); // forbid copying of this class
-    CharString &operator=(const CharString &other); // forbid copying of this class
+    CharString(const CharString &other) = delete; // forbid copying of this class
+    CharString &operator=(const CharString &other) = delete; // forbid copying of this class
 
     /**
      * Returns U_FILE_ALT_SEP_CHAR if found in string, and U_FILE_SEP_CHAR is not found.
diff --git a/icu4c/source/common/cstr.h b/icu4c/source/common/cstr.h
index c7a77a0ae5a..be21d910bb4 100644
--- a/icu4c/source/common/cstr.h
+++ b/icu4c/source/common/cstr.h
@@ -51,8 +51,8 @@ class U_COMMON_API CStr : public UMemory {
 
   private:
     CharString s;
-    CStr(const CStr &other);               //  Forbid copying of this class.
-    CStr &operator =(const CStr &other);   //  Forbid assignment.
+    CStr(const CStr &other) = delete;               //  Forbid copying of this class.
+    CStr &operator =(const CStr &other) = delete;   //  Forbid assignment.
 };
 
 U_NAMESPACE_END
diff --git a/icu4c/source/common/hash.h b/icu4c/source/common/hash.h
index b927ddb3c36..c9afeaf562e 100644
--- a/icu4c/source/common/hash.h
+++ b/icu4c/source/common/hash.h
@@ -115,8 +115,8 @@ public:
 
     inline UBool equals(const Hashtable& that) const;
 private:
-    Hashtable(const Hashtable &other); // forbid copying of this class
-    Hashtable &operator=(const Hashtable &other); // forbid copying of this class
+    Hashtable(const Hashtable &other) = delete; // forbid copying of this class
+    Hashtable &operator=(const Hashtable &other) = delete; // forbid copying of this class
 };
 
 /*********************************************************************
diff --git a/icu4c/source/common/messageimpl.h b/icu4c/source/common/messageimpl.h
index a56479066bc..061df9189d5 100644
--- a/icu4c/source/common/messageimpl.h
+++ b/icu4c/source/common/messageimpl.h
@@ -55,7 +55,7 @@ public:
                                                             UnicodeString &result);
 
 private:
-    MessageImpl();  // no constructor: all static methods
+    MessageImpl() = delete;  // no constructor: all static methods
 };
 
 U_NAMESPACE_END
diff --git a/icu4c/source/common/normalizer2impl.h b/icu4c/source/common/normalizer2impl.h
index 5c971772c07..449e7783848 100644
--- a/icu4c/source/common/normalizer2impl.h
+++ b/icu4c/source/common/normalizer2impl.h
@@ -131,7 +131,7 @@ public:
         }
     }
 private:
-    Hangul();  // no instantiation
+    Hangul() = delete;  // no instantiation
 };
 
 class Normalizer2Impl;
@@ -759,7 +759,7 @@ public:
     // Must be used only when it is known that norm2 is a Normalizer2WithImpl instance.
     static const Normalizer2Impl *getImpl(const Normalizer2 *norm2);
 private:
-    Normalizer2Factory();  // No instantiation.
+    Normalizer2Factory() = delete;  // No instantiation.
 };
 
 U_NAMESPACE_END
diff --git a/icu4c/source/common/patternprops.h b/icu4c/source/common/patternprops.h
index 95898d580c8..4ead56e1cdb 100644
--- a/icu4c/source/common/patternprops.h
+++ b/icu4c/source/common/patternprops.h
@@ -90,7 +90,7 @@ public:
     static const UChar *skipIdentifier(const UChar *s, int32_t length);
 
 private:
-    PatternProps();  // no constructor: all static methods
+    PatternProps() = delete;  // no constructor: all static methods
 };
 
 U_NAMESPACE_END
diff --git a/icu4c/source/common/rbbirb.h b/icu4c/source/common/rbbirb.h
index 11dbf343ece..d983a184b64 100644
--- a/icu4c/source/common/rbbirb.h
+++ b/icu4c/source/common/rbbirb.h
@@ -54,8 +54,8 @@ public:                                       //   of these structs for each ent
     ~RBBISymbolTableEntry();
 
 private:
-    RBBISymbolTableEntry(const RBBISymbolTableEntry &other); // forbid copying of this class
-    RBBISymbolTableEntry &operator=(const RBBISymbolTableEntry &other); // forbid copying of this class
+    RBBISymbolTableEntry(const RBBISymbolTableEntry &other) = delete; // forbid copying of this class
+    RBBISymbolTableEntry &operator=(const RBBISymbolTableEntry &other) = delete; // forbid copying of this class
 };
 
 
@@ -177,8 +177,8 @@ public:
     RBBIDataHeader                *flattenData();    // Create the flattened (runtime format)
                                                      // data tables..
 private:
-    RBBIRuleBuilder(const RBBIRuleBuilder &other); // forbid copying of this class
-    RBBIRuleBuilder &operator=(const RBBIRuleBuilder &other); // forbid copying of this class
+    RBBIRuleBuilder(const RBBIRuleBuilder &other) = delete; // forbid copying of this class
+    RBBIRuleBuilder &operator=(const RBBIRuleBuilder &other) = delete; // forbid copying of this class
 };
 
 
diff --git a/icu4c/source/common/rbbiscan.h b/icu4c/source/common/rbbiscan.h
index 33fdf033546..bf3203880bc 100644
--- a/icu4c/source/common/rbbiscan.h
+++ b/icu4c/source/common/rbbiscan.h
@@ -158,8 +158,8 @@ private:
     UnicodeSet *gRuleSet_name_char;
     UnicodeSet *gRuleSet_name_start_char;
 
-    RBBIRuleScanner(const RBBIRuleScanner &other); // forbid copying of this class
-    RBBIRuleScanner &operator=(const RBBIRuleScanner &other); // forbid copying of this class
+    RBBIRuleScanner(const RBBIRuleScanner &other) = delete; // forbid copying of this class
+    RBBIRuleScanner &operator=(const RBBIRuleScanner &other) = delete; // forbid copying of this class
 };
 
 U_NAMESPACE_END
diff --git a/icu4c/source/common/rbbisetb.h b/icu4c/source/common/rbbisetb.h
index 6409a4ea579..cd09d3317a3 100644
--- a/icu4c/source/common/rbbisetb.h
+++ b/icu4c/source/common/rbbisetb.h
@@ -134,8 +134,8 @@ private:
 
     UBool                 fSawBOF;
 
-    RBBISetBuilder(const RBBISetBuilder &other); // forbid copying of this class
-    RBBISetBuilder &operator=(const RBBISetBuilder &other); // forbid copying of this class
+    RBBISetBuilder(const RBBISetBuilder &other) = delete; // forbid copying of this class
+    RBBISetBuilder &operator=(const RBBISetBuilder &other) = delete; // forbid copying of this class
 };
 
 
diff --git a/icu4c/source/common/rbbitblb.h b/icu4c/source/common/rbbitblb.h
index 38607a819ac..2ac66da11f0 100644
--- a/icu4c/source/common/rbbitblb.h
+++ b/icu4c/source/common/rbbitblb.h
@@ -219,8 +219,8 @@ public:
     ~RBBIStateDescriptor();
 
 private:
-    RBBIStateDescriptor(const RBBIStateDescriptor &other); // forbid copying of this class
-    RBBIStateDescriptor &operator=(const RBBIStateDescriptor &other); // forbid copying of this class
+    RBBIStateDescriptor(const RBBIStateDescriptor &other) = delete; // forbid copying of this class
+    RBBIStateDescriptor &operator=(const RBBIStateDescriptor &other) = delete; // forbid copying of this class
 };
 
 
diff --git a/icu4c/source/common/resource.h b/icu4c/source/common/resource.h
index 48f5b9fa6ec..1483f7d6bcc 100644
--- a/icu4c/source/common/resource.h
+++ b/icu4c/source/common/resource.h
@@ -286,8 +286,8 @@ public:
                      UErrorCode &errorCode) = 0;
 
 private:
-    ResourceSink(const ResourceSink &);  // no copy constructor
-    ResourceSink &operator=(const ResourceSink &);  // no assignment operator
+    ResourceSink(const ResourceSink &) = delete;  // no copy constructor
+    ResourceSink &operator=(const ResourceSink &) = delete;  // no assignment operator
 };
 
 U_NAMESPACE_END
diff --git a/icu4c/source/common/sharedobject.h b/icu4c/source/common/sharedobject.h
index 6ccfb27b018..6298662bbaf 100644
--- a/icu4c/source/common/sharedobject.h
+++ b/icu4c/source/common/sharedobject.h
@@ -38,8 +38,8 @@ public:
 
     virtual ~UnifiedCacheBase();
 private:
-    UnifiedCacheBase(const UnifiedCacheBase &);
-    UnifiedCacheBase &operator=(const UnifiedCacheBase &);
+    UnifiedCacheBase(const UnifiedCacheBase &) = delete;
+    UnifiedCacheBase &operator=(const UnifiedCacheBase &) = delete;
 };
 
 /**
diff --git a/icu4c/source/common/ucase.h b/icu4c/source/common/ucase.h
index 7bf57fd3706..049f0429122 100644
--- a/icu4c/source/common/ucase.h
+++ b/icu4c/source/common/ucase.h
@@ -139,8 +139,8 @@ public:
      */
     UChar32 next(UnicodeString &full);
 private:
-    FullCaseFoldingIterator(const FullCaseFoldingIterator &);  // no copy
-    FullCaseFoldingIterator &operator=(const FullCaseFoldingIterator &);  // no assignment
+    FullCaseFoldingIterator(const FullCaseFoldingIterator &) = delete;  // no copy
+    FullCaseFoldingIterator &operator=(const FullCaseFoldingIterator &) = delete;  // no assignment
 
     const UChar *unfold;
     int32_t unfoldRows;
diff --git a/icu4c/source/common/unicode/bytestrie.h b/icu4c/source/common/unicode/bytestrie.h
index 271a81d1b4d..8fe66780f51 100644
--- a/icu4c/source/common/unicode/bytestrie.h
+++ b/icu4c/source/common/unicode/bytestrie.h
@@ -394,7 +394,7 @@ private:
               pos_(bytes_), remainingMatchLength_(-1) {}
 
     // No assignment operator.
-    BytesTrie &operator=(const BytesTrie &other);
+    BytesTrie &operator=(const BytesTrie &other) = delete;
 
     inline void stop() {
         pos_=NULL;
diff --git a/icu4c/source/common/unicode/bytestriebuilder.h b/icu4c/source/common/unicode/bytestriebuilder.h
index 382f5e0095f..ec9c625473d 100644
--- a/icu4c/source/common/unicode/bytestriebuilder.h
+++ b/icu4c/source/common/unicode/bytestriebuilder.h
@@ -129,8 +129,8 @@ public:
 private:
     friend class ::BytesTrieTest;
 
-    BytesTrieBuilder(const BytesTrieBuilder &other);  // no copy constructor
-    BytesTrieBuilder &operator=(const BytesTrieBuilder &other);  // no assignment operator
+    BytesTrieBuilder(const BytesTrieBuilder &other) = delete;  // no copy constructor
+    BytesTrieBuilder &operator=(const BytesTrieBuilder &other) = delete;  // no assignment operator
 
     void buildBytes(UStringTrieBuildOption buildOption, UErrorCode &errorCode);
 
diff --git a/icu4c/source/common/unicode/caniter.h b/icu4c/source/common/unicode/caniter.h
index 6e57ef5e3ba..db400a531bf 100644
--- a/icu4c/source/common/unicode/caniter.h
+++ b/icu4c/source/common/unicode/caniter.h
@@ -150,20 +150,20 @@ public:
 private:
     // ===================== PRIVATES ==============================
     // private default constructor
-    CanonicalIterator();
+    CanonicalIterator() = delete;
 
 
     /**
      * Copy constructor. Private for now.
      * @internal (private)
      */
-    CanonicalIterator(const CanonicalIterator& other);
+    CanonicalIterator(const CanonicalIterator& other) = delete;
 
     /**
      * Assignment operator. Private for now.
      * @internal (private)
      */
-    CanonicalIterator& operator=(const CanonicalIterator& other);
+    CanonicalIterator& operator=(const CanonicalIterator& other) = delete;
 
     // fields
     UnicodeString source;
diff --git a/icu4c/source/common/unicode/dtintrv.h b/icu4c/source/common/unicode/dtintrv.h
index 46a94ce3495..8c172eb7a59 100644
--- a/icu4c/source/common/unicode/dtintrv.h
+++ b/icu4c/source/common/unicode/dtintrv.h
@@ -131,7 +131,7 @@ private:
     /** 
      * Default constructor, not implemented.
      */
-    DateInterval();
+    DateInterval() = delete;
 
     UDate fromDate;
     UDate toDate;
diff --git a/icu4c/source/common/unicode/idna.h b/icu4c/source/common/unicode/idna.h
index 1305dc60484..1c57205bae2 100644
--- a/icu4c/source/common/unicode/idna.h
+++ b/icu4c/source/common/unicode/idna.h
@@ -305,8 +305,8 @@ public:
 private:
     friend class UTS46;
 
-    IDNAInfo(const IDNAInfo &other);  // no copying
-    IDNAInfo &operator=(const IDNAInfo &other);  // no copying
+    IDNAInfo(const IDNAInfo &other) = delete;  // no copying
+    IDNAInfo &operator=(const IDNAInfo &other) = delete;  // no copying
 
     void reset() {
         errors=labelErrors=0;
diff --git a/icu4c/source/common/unicode/normlzr.h b/icu4c/source/common/unicode/normlzr.h
index 93661990fec..14b24698850 100644
--- a/icu4c/source/common/unicode/normlzr.h
+++ b/icu4c/source/common/unicode/normlzr.h
@@ -740,8 +740,8 @@ private:
   // Private functions
   //-------------------------------------------------------------------------
 
-  Normalizer(); // default constructor not implemented
-  Normalizer &operator=(const Normalizer &that); // assignment operator not implemented
+  Normalizer() = delete; // default constructor not implemented
+  Normalizer &operator=(const Normalizer &that) = delete; // assignment operator not implemented
 
   // Private utility methods for iteration
   // For documentation, see the source code
diff --git a/icu4c/source/common/unicode/resbund.h b/icu4c/source/common/unicode/resbund.h
index 7441592a0f2..6e26a40591f 100644
--- a/icu4c/source/common/unicode/resbund.h
+++ b/icu4c/source/common/unicode/resbund.h
@@ -484,7 +484,7 @@ public:
     static UClassID U_EXPORT2 getStaticClassID();
 
 private:
-    ResourceBundle(); // default constructor not implemented
+    ResourceBundle() = delete; // default constructor not implemented
 
     UResourceBundle *fResource;
     void constructForLocale(const UnicodeString& path, const Locale& locale, UErrorCode& error);
diff --git a/icu4c/source/common/unicode/ucharstrie.h b/icu4c/source/common/unicode/ucharstrie.h
index b6f9e3e075c..064244a74c1 100644
--- a/icu4c/source/common/unicode/ucharstrie.h
+++ b/icu4c/source/common/unicode/ucharstrie.h
@@ -409,7 +409,7 @@ private:
               pos_(uchars_), remainingMatchLength_(-1) {}
 
     // No assignment operator.
-    UCharsTrie &operator=(const UCharsTrie &other);
+    UCharsTrie &operator=(const UCharsTrie &other) = delete;
 
     inline void stop() {
         pos_=NULL;
diff --git a/icu4c/source/common/unicode/ucharstriebuilder.h b/icu4c/source/common/unicode/ucharstriebuilder.h
index e0cb0acdc53..5c8aa33ffb3 100644
--- a/icu4c/source/common/unicode/ucharstriebuilder.h
+++ b/icu4c/source/common/unicode/ucharstriebuilder.h
@@ -133,8 +133,8 @@ public:
     }
 
 private:
-    UCharsTrieBuilder(const UCharsTrieBuilder &other);  // no copy constructor
-    UCharsTrieBuilder &operator=(const UCharsTrieBuilder &other);  // no assignment operator
+    UCharsTrieBuilder(const UCharsTrieBuilder &other) = delete;  // no copy constructor
+    UCharsTrieBuilder &operator=(const UCharsTrieBuilder &other) = delete;  // no assignment operator
 
     void buildUChars(UStringTrieBuildOption buildOption, UErrorCode &errorCode);
 
diff --git a/icu4c/source/common/unifiedcache.h b/icu4c/source/common/unifiedcache.h
index 07a734b8bd5..4b9222124a2 100644
--- a/icu4c/source/common/unifiedcache.h
+++ b/icu4c/source/common/unifiedcache.h
@@ -354,8 +354,8 @@ class U_COMMON_API UnifiedCache : public UnifiedCacheBase {
    mutable int64_t fAutoEvictedCount;
    SharedObject *fNoValue;
    
-   UnifiedCache(const UnifiedCache &other);
-   UnifiedCache &operator=(const UnifiedCache &other);
+   UnifiedCache(const UnifiedCache &other) = delete;
+   UnifiedCache &operator=(const UnifiedCache &other) = delete;
    
    /**
     * Flushes the contents of the cache. If cache values hold references to other
diff --git a/icu4c/source/common/util.h b/icu4c/source/common/util.h
index 7e6d356899f..4a9ae831de3 100644
--- a/icu4c/source/common/util.h
+++ b/icu4c/source/common/util.h
@@ -258,7 +258,7 @@ class U_COMMON_API ICU_Utility /* not : public UObject because all methods are s
 
 private:
     // do not instantiate
-    ICU_Utility();
+    ICU_Utility() = delete;
 };
 
 U_NAMESPACE_END
diff --git a/icu4c/source/common/uvectr32.h b/icu4c/source/common/uvectr32.h
index ecefb7af3ea..a7fada38335 100644
--- a/icu4c/source/common/uvectr32.h
+++ b/icu4c/source/common/uvectr32.h
@@ -187,10 +187,10 @@ private:
     void _init(int32_t initialCapacity, UErrorCode &status);
 
     // Disallow
-    UVector32(const UVector32&);
+    UVector32(const UVector32&) = delete;
 
     // Disallow
-    UVector32& operator=(const UVector32&);
+    UVector32& operator=(const UVector32&) = delete;
 
 
     //  API Functions for Stack operations.
diff --git a/icu4c/source/common/uvectr64.h b/icu4c/source/common/uvectr64.h
index ba3eca268df..070e2dd67d2 100644
--- a/icu4c/source/common/uvectr64.h
+++ b/icu4c/source/common/uvectr64.h
@@ -176,10 +176,10 @@ private:
     void _init(int32_t initialCapacity, UErrorCode &status);
 
     // Disallow
-    UVector64(const UVector64&);
+    UVector64(const UVector64&) = delete;
 
     // Disallow
-    UVector64& operator=(const UVector64&);
+    UVector64& operator=(const UVector64&) = delete;
 
 
     //  API Functions for Stack operations.
diff --git a/icu4c/source/i18n/chnsecal.h b/icu4c/source/i18n/chnsecal.h
index 61ef2d3cad5..488fe169d99 100644
--- a/icu4c/source/i18n/chnsecal.h
+++ b/icu4c/source/i18n/chnsecal.h
@@ -274,7 +274,7 @@ class U_I18N_API ChineseCalendar : public Calendar {
    */
   int32_t          internalGetDefaultCenturyStartYear(void) const;
 
-  ChineseCalendar(); // default constructor not implemented
+  ChineseCalendar() = delete; // default constructor not implemented
 };
 
 U_NAMESPACE_END
diff --git a/icu4c/source/i18n/collation.h b/icu4c/source/i18n/collation.h
index 6a449a3eb69..acd214d7c70 100644
--- a/icu4c/source/i18n/collation.h
+++ b/icu4c/source/i18n/collation.h
@@ -491,7 +491,7 @@ public:
     }
 
 private:
-    Collation();  // No instantiation.
+    Collation() = delete;  // No instantiation.
 };
 
 U_NAMESPACE_END
diff --git a/icu4c/source/i18n/collationdatareader.h b/icu4c/source/i18n/collationdatareader.h
index 44e69399e39..083b57ea580 100644
--- a/icu4c/source/i18n/collationdatareader.h
+++ b/icu4c/source/i18n/collationdatareader.h
@@ -106,7 +106,7 @@ struct U_I18N_API CollationDataReader /* all static */ {
     isAcceptable(void *context, const char *type, const char *name, const UDataInfo *pInfo);
 
 private:
-    CollationDataReader();  // no constructor
+    CollationDataReader() = delete;  // no constructor
 };
 
 /*
diff --git a/icu4c/source/i18n/collationdatawriter.h b/icu4c/source/i18n/collationdatawriter.h
index 197cd5309f2..6ba9a9c2c76 100644
--- a/icu4c/source/i18n/collationdatawriter.h
+++ b/icu4c/source/i18n/collationdatawriter.h
@@ -39,7 +39,7 @@ public:
                                   UErrorCode &errorCode);
 
 private:
-    CollationDataWriter();  // no constructor
+    CollationDataWriter() = delete;  // no constructor
 
     static int32_t write(UBool isBase, const UVersionInfo dataVersion,
                          const CollationData &data, const CollationSettings &settings,
diff --git a/icu4c/source/i18n/collationfastlatin.h b/icu4c/source/i18n/collationfastlatin.h
index 4bac797409d..7013f71ce60 100644
--- a/icu4c/source/i18n/collationfastlatin.h
+++ b/icu4c/source/i18n/collationfastlatin.h
@@ -249,7 +249,7 @@ private:
     static uint32_t getQuaternaries(uint32_t variableTop, uint32_t pair);
 
 private:
-    CollationFastLatin();  // no constructor
+    CollationFastLatin() = delete;  // no constructor
 };
 
 /*
diff --git a/icu4c/source/i18n/collationfcd.h b/icu4c/source/i18n/collationfcd.h
index 3a5738efb24..9620452b97f 100644
--- a/icu4c/source/i18n/collationfcd.h
+++ b/icu4c/source/i18n/collationfcd.h
@@ -123,7 +123,7 @@ public:
     }
 
 private:
-    CollationFCD();  // No instantiation.
+    CollationFCD() = delete;  // No instantiation.
 
     static const uint8_t lcccIndex[2048];
     static const uint8_t tcccIndex[2048];
diff --git a/icu4c/source/i18n/collationiterator.h b/icu4c/source/i18n/collationiterator.h
index 73cb93b934a..93c119c6b85 100644
--- a/icu4c/source/i18n/collationiterator.h
+++ b/icu4c/source/i18n/collationiterator.h
@@ -92,8 +92,8 @@ private:
         int32_t length;
 
     private:
-        CEBuffer(const CEBuffer &);
-        void operator=(const CEBuffer &);
+        CEBuffer(const CEBuffer &) = delete;
+        void operator=(const CEBuffer &) = delete;
 
         MaybeStackArray<int64_t, INITIAL_CAPACITY> buffer;
     };
diff --git a/icu4c/source/i18n/collationkeys.h b/icu4c/source/i18n/collationkeys.h
index 5b41d14c0b6..8dad286dc64 100644
--- a/icu4c/source/i18n/collationkeys.h
+++ b/icu4c/source/i18n/collationkeys.h
@@ -116,7 +116,7 @@ public:
 private:
     friend struct CollationDataReader;
 
-    CollationKeys();  // no instantiation
+    CollationKeys() = delete;  // no instantiation
 
     // Secondary level: Compress up to 33 common weights as 05..25 or 25..45.
     static const uint32_t SEC_COMMON_LOW = Collation::COMMON_BYTE;
diff --git a/icu4c/source/i18n/collationtailoring.h b/icu4c/source/i18n/collationtailoring.h
index 5fc2bac2d30..3de9682f950 100644
--- a/icu4c/source/i18n/collationtailoring.h
+++ b/icu4c/source/i18n/collationtailoring.h
@@ -89,7 +89,7 @@ private:
      * No copy constructor: A CollationTailoring cannot be copied.
      * It is immutable, and the data trie cannot be copied either.
      */
-    CollationTailoring(const CollationTailoring &other);
+    CollationTailoring(const CollationTailoring &other) = delete;
 };
 
 struct U_I18N_API CollationCacheEntry : public SharedObject {
diff --git a/icu4c/source/i18n/indiancal.h b/icu4c/source/i18n/indiancal.h
index 029515cf547..bfbea003295 100644
--- a/icu4c/source/i18n/indiancal.h
+++ b/icu4c/source/i18n/indiancal.h
@@ -285,7 +285,7 @@ public:
   virtual const char * getType() const override;
 
 private:
-  IndianCalendar(); // default constructor not implemented
+  IndianCalendar() = delete; // default constructor not implemented
 
   // Default century.
 protected:
diff --git a/icu4c/source/i18n/islamcal.h b/icu4c/source/i18n/islamcal.h
index a29b7daa086..7d9941d4709 100644
--- a/icu4c/source/i18n/islamcal.h
+++ b/icu4c/source/i18n/islamcal.h
@@ -377,7 +377,7 @@ class U_I18N_API IslamicCalendar : public Calendar {
   virtual const char * getType() const override;
 
  private:
-  IslamicCalendar(); // default constructor not implemented
+  IslamicCalendar() = delete; // default constructor not implemented
 
   // Default century.
  protected:
diff --git a/icu4c/source/i18n/nfsubs.h b/icu4c/source/i18n/nfsubs.h
index 0abd98be097..a38a3722a59 100644
--- a/icu4c/source/i18n/nfsubs.h
+++ b/icu4c/source/i18n/nfsubs.h
@@ -245,8 +245,8 @@ public:
     virtual UBool isModulusSubstitution() const;
     
 private:
-    NFSubstitution(const NFSubstitution &other); // forbid copying of this class
-    NFSubstitution &operator=(const NFSubstitution &other); // forbid copying of this class
+    NFSubstitution(const NFSubstitution &other) = delete; // forbid copying of this class
+    NFSubstitution &operator=(const NFSubstitution &other) = delete; // forbid copying of this class
 
 public:
     static UClassID getStaticClassID(void);
diff --git a/icu4c/source/i18n/sharedbreakiterator.h b/icu4c/source/i18n/sharedbreakiterator.h
index b6d67bc8e8e..76e959fda3e 100644
--- a/icu4c/source/i18n/sharedbreakiterator.h
+++ b/icu4c/source/i18n/sharedbreakiterator.h
@@ -38,8 +38,8 @@ public:
     BreakIterator &operator*() const { return *ptr; }
 private:
     BreakIterator *ptr;
-    SharedBreakIterator(const SharedBreakIterator &);
-    SharedBreakIterator &operator=(const SharedBreakIterator &);
+    SharedBreakIterator(const SharedBreakIterator &) = delete;
+    SharedBreakIterator &operator=(const SharedBreakIterator &) = delete;
 };
 
 U_NAMESPACE_END
diff --git a/icu4c/source/i18n/sharedcalendar.h b/icu4c/source/i18n/sharedcalendar.h
index 1526f92e88f..7daebaa4086 100644
--- a/icu4c/source/i18n/sharedcalendar.h
+++ b/icu4c/source/i18n/sharedcalendar.h
@@ -27,8 +27,8 @@ public:
     const Calendar &operator*() const { return *ptr; }
 private:
     Calendar *ptr;
-    SharedCalendar(const SharedCalendar &);
-    SharedCalendar &operator=(const SharedCalendar &);
+    SharedCalendar(const SharedCalendar &) = delete;
+    SharedCalendar &operator=(const SharedCalendar &) = delete;
 };
 
 U_NAMESPACE_END
diff --git a/icu4c/source/i18n/shareddateformatsymbols.h b/icu4c/source/i18n/shareddateformatsymbols.h
index 66a06ecae54..92298a83e32 100644
--- a/icu4c/source/i18n/shareddateformatsymbols.h
+++ b/icu4c/source/i18n/shareddateformatsymbols.h
@@ -30,8 +30,8 @@ public:
     const DateFormatSymbols &get() const { return dfs; }
 private:
     DateFormatSymbols dfs;
-    SharedDateFormatSymbols(const SharedDateFormatSymbols &);
-    SharedDateFormatSymbols &operator=(const SharedDateFormatSymbols &);
+    SharedDateFormatSymbols(const SharedDateFormatSymbols &) = delete;
+    SharedDateFormatSymbols &operator=(const SharedDateFormatSymbols &) = delete;
 };
 
 U_NAMESPACE_END
diff --git a/icu4c/source/i18n/sharednumberformat.h b/icu4c/source/i18n/sharednumberformat.h
index a7e105b5ac1..7ea756a779d 100644
--- a/icu4c/source/i18n/sharednumberformat.h
+++ b/icu4c/source/i18n/sharednumberformat.h
@@ -27,8 +27,8 @@ public:
     const NumberFormat &operator*() const { return *ptr; }
 private:
     NumberFormat *ptr;
-    SharedNumberFormat(const SharedNumberFormat &);
-    SharedNumberFormat &operator=(const SharedNumberFormat &);
+    SharedNumberFormat(const SharedNumberFormat &) = delete;
+    SharedNumberFormat &operator=(const SharedNumberFormat &) = delete;
 };
 
 U_NAMESPACE_END
diff --git a/icu4c/source/i18n/sharedpluralrules.h b/icu4c/source/i18n/sharedpluralrules.h
index 28d8b25c14b..f543797a802 100644
--- a/icu4c/source/i18n/sharedpluralrules.h
+++ b/icu4c/source/i18n/sharedpluralrules.h
@@ -26,8 +26,8 @@ public:
     const PluralRules &operator*() const { return *ptr; }
 private:
     PluralRules *ptr;
-    SharedPluralRules(const SharedPluralRules &);
-    SharedPluralRules &operator=(const SharedPluralRules &);
+    SharedPluralRules(const SharedPluralRules &) = delete;
+    SharedPluralRules &operator=(const SharedPluralRules &) =delete;
 };
 
 U_NAMESPACE_END
diff --git a/icu4c/source/i18n/unicode/alphaindex.h b/icu4c/source/i18n/unicode/alphaindex.h
index d0cdd817fba..ec50822d589 100644
--- a/icu4c/source/i18n/unicode/alphaindex.h
+++ b/icu4c/source/i18n/unicode/alphaindex.h
@@ -649,7 +649,7 @@ private:
       * No Copy constructor.
       * @internal (private)
       */
-     AlphabeticIndex(const AlphabeticIndex &other);
+     AlphabeticIndex(const AlphabeticIndex &other) = delete;
 
      /**
       *   No assignment.
diff --git a/icu4c/source/i18n/unicode/choicfmt.h b/icu4c/source/i18n/unicode/choicfmt.h
index 0e7ae186d4d..66f437e52f0 100644
--- a/icu4c/source/i18n/unicode/choicfmt.h
+++ b/icu4c/source/i18n/unicode/choicfmt.h
@@ -478,7 +478,7 @@ private:
      */
     static UnicodeString& dtos(double value, UnicodeString& string);
 
-    ChoiceFormat(); // default constructor not implemented
+    ChoiceFormat() = delete; // default constructor not implemented
 
     /**
      * Construct a new ChoiceFormat with the limits and the corresponding formats
diff --git a/icu4c/source/i18n/unicode/coleitr.h b/icu4c/source/i18n/unicode/coleitr.h
index 4e68c6f1749..d3ddd0ee044 100644
--- a/icu4c/source/i18n/unicode/coleitr.h
+++ b/icu4c/source/i18n/unicode/coleitr.h
@@ -351,7 +351,7 @@ private:
     const CollationElementIterator&
         operator=(const CollationElementIterator& other);
 
-    CollationElementIterator(); // default constructor not implemented
+    CollationElementIterator() = delete; // default constructor not implemented
 
     /** Normalizes dir_=1 (just after setOffset()) to dir_=0 (just after reset()). */
     inline int8_t normalizeDir() const { return dir_ == 1 ? 0 : dir_; }
diff --git a/icu4c/source/i18n/unicode/coll.h b/icu4c/source/i18n/unicode/coll.h
index 9e0050ba6ce..6aa35bb5b74 100644
--- a/icu4c/source/i18n/unicode/coll.h
+++ b/icu4c/source/i18n/unicode/coll.h
@@ -1202,7 +1202,7 @@ private:
     /**
      * Assignment operator. Private for now.
      */
-    Collator& operator=(const Collator& other);
+    Collator& operator=(const Collator& other) = delete;
 
     friend class CFactory;
     friend class SimpleCFactory;
diff --git a/icu4c/source/i18n/unicode/dtfmtsym.h b/icu4c/source/i18n/unicode/dtfmtsym.h
index 200b3a6ef17..9dbd7288375 100644
--- a/icu4c/source/i18n/unicode/dtfmtsym.h
+++ b/icu4c/source/i18n/unicode/dtfmtsym.h
@@ -920,7 +920,7 @@ private:
     char validLocale[ULOC_FULLNAME_CAPACITY];
     char actualLocale[ULOC_FULLNAME_CAPACITY];
 
-    DateFormatSymbols(); // default constructor not implemented
+    DateFormatSymbols() = delete; // default constructor not implemented
 
     /**
      * Called by the constructors to actually load data from the resources
diff --git a/icu4c/source/i18n/unicode/gender.h b/icu4c/source/i18n/unicode/gender.h
index cf7fee963e1..c81f7c88cc4 100644
--- a/icu4c/source/i18n/unicode/gender.h
+++ b/icu4c/source/i18n/unicode/gender.h
@@ -91,12 +91,12 @@ private:
      * Copy constructor. One object per locale invariant. Clients
      * must never copy GenderInfo objects.
      */
-    GenderInfo(const GenderInfo& other);
+    GenderInfo(const GenderInfo& other) = delete;
 
     /**
       * Assignment operator. Not applicable to immutable objects.
       */
-    GenderInfo& operator=(const GenderInfo&);
+    GenderInfo& operator=(const GenderInfo&) = delete;
 
     GenderInfo();
 
diff --git a/icu4c/source/i18n/unicode/gregocal.h b/icu4c/source/i18n/unicode/gregocal.h
index 4c2be18251f..91b68bb2f50 100644
--- a/icu4c/source/i18n/unicode/gregocal.h
+++ b/icu4c/source/i18n/unicode/gregocal.h
@@ -487,7 +487,7 @@ public:
     virtual const char * getType() const override;
 
  private:
-    GregorianCalendar(); // default constructor not implemented
+    GregorianCalendar() = delete; // default constructor not implemented
 
  protected:
     /**
diff --git a/icu4c/source/i18n/unicode/listformatter.h b/icu4c/source/i18n/unicode/listformatter.h
index d7ab1d20865..9ce0427640e 100644
--- a/icu4c/source/i18n/unicode/listformatter.h
+++ b/icu4c/source/i18n/unicode/listformatter.h
@@ -275,7 +275,7 @@ class U_I18N_API ListFormatter : public UObject{
         const UnicodeString items[], int32_t n_items, UnicodeString& appendTo,
         int32_t index, int32_t &offset, FieldPositionHandler* handler, UErrorCode& errorCode) const;
 
-    ListFormatter();
+    ListFormatter() = delete;
 
     ListFormatInternal* owned;
     const ListFormatInternal* data;
diff --git a/icu4c/source/i18n/unicode/msgfmt.h b/icu4c/source/i18n/unicode/msgfmt.h
index c949132fdae..c27b2ebf523 100644
--- a/icu4c/source/i18n/unicode/msgfmt.h
+++ b/icu4c/source/i18n/unicode/msgfmt.h
@@ -886,7 +886,7 @@ private:
     Format**            formatAliases; // see getFormats
     int32_t             formatAliasesCapacity;
 
-    MessageFormat(); // default constructor not implemented
+    MessageFormat() = delete; // default constructor not implemented
 
      /**
       * This provider helps defer instantiation of a PluralRules object
diff --git a/icu4c/source/i18n/unicode/plurfmt.h b/icu4c/source/i18n/unicode/plurfmt.h
index db160546057..1bdc3693413 100644
--- a/icu4c/source/i18n/unicode/plurfmt.h
+++ b/icu4c/source/i18n/unicode/plurfmt.h
@@ -561,7 +561,7 @@ private:
     double offset;
     PluralSelectorAdapter pluralRulesWrapper;
 
-    PluralFormat();   // default constructor not implemented
+    PluralFormat() = delete;   // default constructor not implemented
     void init(const PluralRules* rules, UPluralType type, UErrorCode& status);
     /**
      * Copies dynamically allocated values (pointer fields).
diff --git a/icu4c/source/i18n/unicode/plurrule.h b/icu4c/source/i18n/unicode/plurrule.h
index e90cd66a7f7..b8d1b051e98 100644
--- a/icu4c/source/i18n/unicode/plurrule.h
+++ b/icu4c/source/i18n/unicode/plurrule.h
@@ -569,7 +569,7 @@ private:
     RuleChain  *mRules;
     StandardPluralRanges *mStandardPluralRanges;
 
-    PluralRules();   // default constructor not implemented
+    PluralRules() = delete;   // default constructor not implemented
     void            parseDescription(const UnicodeString& ruleData, UErrorCode &status);
     int32_t         getNumberValue(const UnicodeString& token) const;
     UnicodeString   getRuleFromResource(const Locale& locale, UPluralType type, UErrorCode& status);
diff --git a/icu4c/source/i18n/unicode/rbnf.h b/icu4c/source/i18n/unicode/rbnf.h
index 0a5a378e13b..d4d7e225181 100644
--- a/icu4c/source/i18n/unicode/rbnf.h
+++ b/icu4c/source/i18n/unicode/rbnf.h
@@ -1040,7 +1040,7 @@ public:
     virtual void setDecimalFormatSymbols(const DecimalFormatSymbols& symbols);
 
 private:
-    RuleBasedNumberFormat(); // default constructor not implemented
+    RuleBasedNumberFormat() = delete; // default constructor not implemented
 
     // this will ref the localizations if they are not NULL
     // caller must deref to get adoption
diff --git a/icu4c/source/i18n/unicode/regex.h b/icu4c/source/i18n/unicode/regex.h
index f8e32922f4e..7337689a54b 100644
--- a/icu4c/source/i18n/unicode/regex.h
+++ b/icu4c/source/i18n/unicode/regex.h
@@ -1751,10 +1751,10 @@ public:
 private:
     // Constructors and other object boilerplate are private.
     // Instances of RegexMatcher can not be assigned, copied, cloned, etc.
-    RegexMatcher();                  // default constructor not implemented
+    RegexMatcher() = delete;                  // default constructor not implemented
     RegexMatcher(const RegexPattern *pat);
-    RegexMatcher(const RegexMatcher &other);
-    RegexMatcher &operator =(const RegexMatcher &rhs);
+    RegexMatcher(const RegexMatcher &other) = delete;
+    RegexMatcher &operator =(const RegexMatcher &rhs) = delete;
     void init(UErrorCode &status);                      // Common initialization
     void init2(UText *t, UErrorCode &e);  // Common initialization, part 2.
 
diff --git a/icu4c/source/i18n/unicode/scientificnumberformatter.h b/icu4c/source/i18n/unicode/scientificnumberformatter.h
index aa7e80543e4..a1dd5436382 100644
--- a/icu4c/source/i18n/unicode/scientificnumberformatter.h
+++ b/icu4c/source/i18n/unicode/scientificnumberformatter.h
@@ -196,7 +196,7 @@ public:
             UErrorCode &status);
 
     ScientificNumberFormatter(const ScientificNumberFormatter &other);
-    ScientificNumberFormatter &operator=(const ScientificNumberFormatter &);
+    ScientificNumberFormatter &operator=(const ScientificNumberFormatter &) = delete;
 
     static void getPreExponent(
             const DecimalFormatSymbols &dfs, UnicodeString &preExponent);
diff --git a/icu4c/source/i18n/unicode/selfmt.h b/icu4c/source/i18n/unicode/selfmt.h
index bdce00e593e..18023803127 100644
--- a/icu4c/source/i18n/unicode/selfmt.h
+++ b/icu4c/source/i18n/unicode/selfmt.h
@@ -348,7 +348,7 @@ public:
 private:
     friend class MessageFormat;
 
-    SelectFormat();   // default constructor not implemented.
+    SelectFormat() = delete;   // default constructor not implemented.
 
     /**
      * Finds the SelectFormat sub-message for the given keyword, or the "other" sub-message.
diff --git a/icu4c/source/i18n/unicode/simpletz.h b/icu4c/source/i18n/unicode/simpletz.h
index f73d823ee58..cbdba7aff6e 100644
--- a/icu4c/source/i18n/unicode/simpletz.h
+++ b/icu4c/source/i18n/unicode/simpletz.h
@@ -800,7 +800,7 @@ private:
         DOW_LE_DOM_MODE
     };
 
-    SimpleTimeZone(); // default constructor not implemented
+    SimpleTimeZone() = delete; // default constructor not implemented
 
     /**
      * Internal construction method.
diff --git a/icu4c/source/i18n/unicode/smpdtfmt.h b/icu4c/source/i18n/unicode/smpdtfmt.h
index 733a1cff13b..d1b2cd7d74e 100644
--- a/icu4c/source/i18n/unicode/smpdtfmt.h
+++ b/icu4c/source/i18n/unicode/smpdtfmt.h
@@ -1226,7 +1226,7 @@ private:
 
     void initializeBooleanAttributes(void);
 
-    SimpleDateFormat(); // default constructor not implemented
+    SimpleDateFormat() = delete; // default constructor not implemented
 
     /**
      * Used by the DateFormat factory methods to construct a SimpleDateFormat.
diff --git a/icu4c/source/i18n/unicode/stsearch.h b/icu4c/source/i18n/unicode/stsearch.h
index c23e651d897..b8a919f6147 100644
--- a/icu4c/source/i18n/unicode/stsearch.h
+++ b/icu4c/source/i18n/unicode/stsearch.h
@@ -482,7 +482,7 @@ protected:
     virtual int32_t handlePrev(int32_t position, UErrorCode &status) override;
     
 private :
-    StringSearch(); // default constructor not implemented
+    StringSearch() = delete; // default constructor not implemented
 
     // private data members ----------------------------------------------
 
diff --git a/icu4c/source/i18n/zonemeta.h b/icu4c/source/i18n/zonemeta.h
index dd4fec957fe..97c0e6057d7 100644
--- a/icu4c/source/i18n/zonemeta.h
+++ b/icu4c/source/i18n/zonemeta.h
@@ -113,7 +113,7 @@ public:
     static const UChar* U_EXPORT2 getShortID(const UnicodeString& id);
 
 private:
-    ZoneMeta(); // Prevent construction.
+    ZoneMeta() = delete; // Prevent construction.
     static UVector* createMetazoneMappings(const UnicodeString &tzid);
     static UnicodeString& formatCustomID(uint8_t hour, uint8_t min, uint8_t sec, UBool negative, UnicodeString& id);
     static const UChar* getShortIDFromCanonical(const UChar* canonicalID);