diff --git a/icu4c/source/i18n/ucol_tok.cpp b/icu4c/source/i18n/ucol_tok.cpp
index 9206687d453..732fbc704ba 100644
--- a/icu4c/source/i18n/ucol_tok.cpp
+++ b/icu4c/source/i18n/ucol_tok.cpp
@@ -64,7 +64,7 @@ void ucol_tok_initTokenList(UColTokenParser *src, const UChar *rules, const uint
   src->resultLen = 0;
 }
 
-U_INLINE void 
+inline void 
 syntaxError(   const UChar* rules, 
                int32_t pos,
                int32_t rulesLen,