diff --git a/icu4c/source/common/sharedobject.h b/icu4c/source/common/sharedobject.h
index 203a3387be..ed79a6a73e 100644
--- a/icu4c/source/common/sharedobject.h
+++ b/icu4c/source/common/sharedobject.h
@@ -30,7 +30,7 @@ public:
     SharedObject() : refCount(0) {}
 
     /** Initializes refCount to 0. */
-    SharedObject(const SharedObject &/*other*/) : refCount(0) {}
+    SharedObject(const SharedObject &other) : UObject(other), refCount(0) {}
     virtual ~SharedObject();
 
     /**
diff --git a/icu4c/source/i18n/reldatefmt.cpp b/icu4c/source/i18n/reldatefmt.cpp
index 1ad63fe111..9041dba21f 100644
--- a/icu4c/source/i18n/reldatefmt.cpp
+++ b/icu4c/source/i18n/reldatefmt.cpp
@@ -726,7 +726,8 @@ RelativeDateTimeFormatter::RelativeDateTimeFormatter(
 
 RelativeDateTimeFormatter::RelativeDateTimeFormatter(
         const RelativeDateTimeFormatter& other)
-        : fCache(other.fCache),
+        : UObject(other),
+          fCache(other.fCache),
           fNumberFormat(other.fNumberFormat),
           fPluralRules(other.fPluralRules),
           fStyle(other.fStyle),