diff --git a/icu4c/source/common/unicode/dbbi.h b/icu4c/source/common/unicode/dbbi.h
index 642d8ba6dd..4653c1e26f 100644
--- a/icu4c/source/common/unicode/dbbi.h
+++ b/icu4c/source/common/unicode/dbbi.h
@@ -199,7 +199,7 @@ public:
      * @return          The class ID for all objects of this class.
      * @stable ICU 2.0
      */
-    static UClassID getStaticClassID(void);
+    static inline UClassID getStaticClassID(void);
 
 protected:
     //=======================================================================