diff --git a/icu4c/source/common/bytesinkutil.h b/icu4c/source/common/bytesinkutil.h
index ab2516432d3..929c71fbee6 100644
--- a/icu4c/source/common/bytesinkutil.h
+++ b/icu4c/source/common/bytesinkutil.h
@@ -4,6 +4,9 @@
 // bytesinkutil.h
 // created: 2017sep14 Markus W. Scherer
 
+#ifndef BYTESINKUTIL_H
+#define BYTESINKUTIL_H
+
 #include "unicode/utypes.h"
 #include "unicode/bytestream.h"
 #include "unicode/edits.h"
@@ -81,3 +84,5 @@ private:
 };
 
 U_NAMESPACE_END
+
+#endif //BYTESINKUTIL_H
diff --git a/icu4c/source/i18n/vzone.h b/icu4c/source/i18n/vzone.h
index d1b6d8d8204..bf9b45ea20d 100644
--- a/icu4c/source/i18n/vzone.h
+++ b/icu4c/source/i18n/vzone.h
@@ -24,14 +24,12 @@
 #include "unicode/uobject.h"
 #include "ztrans.h"
 
-#ifndef UCNV_H
 struct VZone;
 /**
  * A UnicodeSet.  Use the vzone_* API to manipulate.  Create with
  * vzone_open*, and destroy with vzone_close.
  */
 typedef struct VZone VZone;
-#endif
 
 /*********************************************************************
  * VZone API
diff --git a/icu4c/source/i18n/zrule.h b/icu4c/source/i18n/zrule.h
index f395ad4c3f3..2bea64c6d4f 100644
--- a/icu4c/source/i18n/zrule.h
+++ b/icu4c/source/i18n/zrule.h
@@ -20,8 +20,6 @@
 
 #include "unicode/uobject.h"
 
-#ifndef UCNV_H
-
 /**
  * A TimeZoneRule.  Use the zrule_* API to manipulate.  Create with
  * zrule_open*, and destroy with zrule_close.
@@ -43,8 +41,6 @@ typedef struct IZRule IZRule;
 struct AZRule;
 typedef struct AZRule AZRule;
 
-#endif
-
 /*********************************************************************
  * ZRule API
  *********************************************************************/
diff --git a/icu4c/source/i18n/ztrans.h b/icu4c/source/i18n/ztrans.h
index b23bb4fc706..a1f39100557 100644
--- a/icu4c/source/i18n/ztrans.h
+++ b/icu4c/source/i18n/ztrans.h
@@ -20,8 +20,6 @@
 
 #include "unicode/uobject.h"
 
-#ifndef UCNV_H
-
 /**
  * A TimeZoneTransition.  Use the ztrans_* API to manipulate.  Create with
  * ztrans_open*, and destroy with ztrans_close.
@@ -29,8 +27,6 @@
 struct ZTrans;
 typedef struct ZTrans ZTrans;
 
-#endif
-
 /**
  * Constructs a time zone transition with the time and the rules before/after
  * the transition.