diff --git a/icu4c/source/common/rbbiscan.cpp b/icu4c/source/common/rbbiscan.cpp
index f3389485208..9f9947e6839 100644
--- a/icu4c/source/common/rbbiscan.cpp
+++ b/icu4c/source/common/rbbiscan.cpp
@@ -716,7 +716,7 @@ UnicodeString RBBIRuleScanner::stripRules(const UnicodeString &rules) {
                 ch = rules[idx++];
             }
         }
-        if (!u_isWhitespace(ch)) {
+        if (!u_isISOControl(ch)) {
             strippedRules.append(ch);
         }
     }