diff --git a/icu4c/source/common/unicode/unistr.h b/icu4c/source/common/unicode/unistr.h
index a2ce193c455..c5389d68adc 100644
--- a/icu4c/source/common/unicode/unistr.h
+++ b/icu4c/source/common/unicode/unistr.h
@@ -57,14 +57,35 @@ class StringSearch;
  * @stable
  */
 #if U_SIZEOF_WCHAR_T==U_SIZEOF_UCHAR && U_CHARSET_FAMILY==U_ASCII_FAMILY
-#   define UNICODE_STRING(cs, length) UnicodeString(TRUE, (UChar *)L ## cs, length)
+#   define UNICODE_STRING(cs, length) UnicodeString(TRUE, (const UChar *)L ## cs, length)
 #elif U_SIZEOF_UCHAR==1 && U_CHARSET_FAMILY==U_ASCII_FAMILY
-#   define UNICODE_STRING(cs, length) UnicodeString(TRUE, (UChar *)cs, length)
+#   define UNICODE_STRING(cs, length) UnicodeString(TRUE, (const UChar *)cs, length)
 #else
 #   define UNICODE_STRING(cs, length) UnicodeString(cs, length, "")
 #endif
 
 /**
+ * Unicode String literals in C++.
+ * Dependent on the platform properties, different UnicodeString
+ * constructors should be used to create a UnicodeString object from
+ * a string literal.
+ * The macros are defined for improved performance.
+ * They work only for strings that contain "invariant characters", i.e.,
+ * only latin letters, digits, and some punctuation.
+ * See utypes.h for details.
+ *
+ * The string parameter must be a C string literal.
+ * @stable
+ */
+#if U_SIZEOF_WCHAR_T==U_SIZEOF_UCHAR && U_CHARSET_FAMILY==U_ASCII_FAMILY
+#   define UNICODE_STRING_SIMPLE(cs) UnicodeString((const UChar *)L ## cs)
+#elif U_SIZEOF_UCHAR==1 && U_CHARSET_FAMILY==U_ASCII_FAMILY
+#   define UNICODE_STRING_SIMPLE(cs) UnicodeString((const UChar *)cs)
+#else
+#   define UNICODE_STRING_SIMPLE(cs) UnicodeString(cs, "")
+#endif
+
+ /**
  * UnicodeString is a string class that stores Unicode characters directly and provides
  * similar functionality as the Java String class.
  * It is a concrete implementation of the abstract class Replaceable (for transliteration).
diff --git a/icu4c/source/i18n/cpdtrans.cpp b/icu4c/source/i18n/cpdtrans.cpp
index 3b247d73747..0958b8eb69f 100644
--- a/icu4c/source/i18n/cpdtrans.cpp
+++ b/icu4c/source/i18n/cpdtrans.cpp
@@ -97,7 +97,7 @@ CompoundTransliterator::CompoundTransliterator(const UnicodeString& newID,
 CompoundTransliterator::CompoundTransliterator(UTransDirection dir,
                                                UVector& list,
                                                UErrorCode& status) :
-    Transliterator(UnicodeString("", ""), 0),
+    Transliterator(UnicodeString(), 0),
     trans(0), compoundRBTIndex(-1)
 {
     init(list, dir, FALSE, status);
diff --git a/icu4c/source/i18n/nortrans.cpp b/icu4c/source/i18n/nortrans.cpp
index cd64b6412b1..dfd6fc7d227 100644
--- a/icu4c/source/i18n/nortrans.cpp
+++ b/icu4c/source/i18n/nortrans.cpp
@@ -129,18 +129,18 @@ void NormalizationTransliterator::registerIDs() {
         return;
     }
 
-    Transliterator::_registerFactory(UnicodeString("Any-NFC", ""),
+    Transliterator::_registerFactory(UNICODE_STRING_SIMPLE("Any-NFC"),
                                      _create, integerToken(UNORM_NFC));
-    Transliterator::_registerFactory(UnicodeString("Any-NFKC", ""),
+    Transliterator::_registerFactory(UNICODE_STRING_SIMPLE("Any-NFKC"),
                                      _create, integerToken(UNORM_NFKC));
-    Transliterator::_registerFactory(UnicodeString("Any-NFD", ""),
+    Transliterator::_registerFactory(UNICODE_STRING_SIMPLE("Any-NFD"),
                                      _create, integerToken(UNORM_NFD));
-    Transliterator::_registerFactory(UnicodeString("Any-NFKD", ""),
+    Transliterator::_registerFactory(UNICODE_STRING_SIMPLE("Any-NFKD"),
                                      _create, integerToken(UNORM_NFKD));
-    Transliterator::_registerSpecialInverse(UnicodeString("NFC", ""),
-                                            UnicodeString("NFD", ""), TRUE);
-    Transliterator::_registerSpecialInverse(UnicodeString("NFKC", ""),
-                                            UnicodeString("NFKD", ""), TRUE);
+    Transliterator::_registerSpecialInverse(UNICODE_STRING_SIMPLE("NFC"),
+                                            UNICODE_STRING_SIMPLE("NFD"), TRUE);
+    Transliterator::_registerSpecialInverse(UNICODE_STRING_SIMPLE("NFKC"),
+                                            UNICODE_STRING_SIMPLE("NFKD"), TRUE);
 }
 
 /**
diff --git a/icu4c/source/i18n/rbt_rule.cpp b/icu4c/source/i18n/rbt_rule.cpp
index bcce2fb5a66..4a9564da5e4 100644
--- a/icu4c/source/i18n/rbt_rule.cpp
+++ b/icu4c/source/i18n/rbt_rule.cpp
@@ -697,7 +697,7 @@ UnicodeString& TransliterationRule::toRule(UnicodeString& rule,
         rule.append((UChar)36/*$*/);
     }
 
-    appendToRule(rule, UnicodeString(" > ", ""), TRUE, escapeUnprintable, quoteBuf);
+    appendToRule(rule, UNICODE_STRING_SIMPLE(" > "), TRUE, escapeUnprintable, quoteBuf);
 
     // Emit the output pattern
 
diff --git a/icu4c/source/i18n/remtrans.cpp b/icu4c/source/i18n/remtrans.cpp
index 1dbd9c5b5bc..f864771cdda 100644
--- a/icu4c/source/i18n/remtrans.cpp
+++ b/icu4c/source/i18n/remtrans.cpp
@@ -20,8 +20,8 @@ void RemoveTransliterator::registerIDs() {
 
     Transliterator::_registerFactory(::ID, _create, integerToken(0));
 
-    Transliterator::_registerSpecialInverse(UnicodeString("Remove", ""),
-                                            UnicodeString("Null", ""), FALSE);
+    Transliterator::_registerSpecialInverse(UNICODE_STRING_SIMPLE("Remove"),
+                                            UNICODE_STRING_SIMPLE("Null"), FALSE);
 }
 
 /**
diff --git a/icu4c/source/i18n/titletrn.cpp b/icu4c/source/i18n/titletrn.cpp
index 40f4c407700..62c3208fc92 100644
--- a/icu4c/source/i18n/titletrn.cpp
+++ b/icu4c/source/i18n/titletrn.cpp
@@ -96,8 +96,8 @@ void TitlecaseTransliterator::handleTransliterate(
         Mutex lock(&MUTEX);
         if (SKIP == NULL) {
             UErrorCode ec = U_ZERO_ERROR;
-            SKIP = new UnicodeSet(UnicodeString("[\\u00AD \\u2019 \\' [:Mn:] [:Me:] [:Cf:] [:Lm:] [:Sk:]]", ""), ec);
-            CASED = new UnicodeSet(UnicodeString("[[:Lu:] [:Ll:] [:Lt:]]", ""), ec);
+            SKIP = new UnicodeSet(UNICODE_STRING_SIMPLE("[\\u00AD \\u2019 \\' [:Mn:] [:Me:] [:Cf:] [:Lm:] [:Sk:]]"), ec);
+            CASED = new UnicodeSet(UNICODE_STRING_SIMPLE("[[:Lu:] [:Ll:] [:Lt:]]"), ec);
             ucln_i18n_registerCleanup();
         }
     }
diff --git a/icu4c/source/i18n/translit.cpp b/icu4c/source/i18n/translit.cpp
index be9ccaaf396..11866ba63c0 100644
--- a/icu4c/source/i18n/translit.cpp
+++ b/icu4c/source/i18n/translit.cpp
@@ -1018,7 +1018,7 @@ UnicodeString& Transliterator::toRules(UnicodeString& rulesSource,
         rulesSource = getID();
     }
     // KEEP in sync with rbt_pars
-    rulesSource.insert(0, UnicodeString("::", ""));
+    rulesSource.insert(0, UNICODE_STRING_SIMPLE("::"));
     rulesSource.append(ID_DELIM);
     return rulesSource;
 }