diff --git a/icu4c/source/i18n/rbt_pars.cpp b/icu4c/source/i18n/rbt_pars.cpp
index 0b7b2ac89b9..ae8dc2906cd 100644
--- a/icu4c/source/i18n/rbt_pars.cpp
+++ b/icu4c/source/i18n/rbt_pars.cpp
@@ -1093,7 +1093,7 @@ UBool TransliteratorParser::checkVariableRange(UChar32 ch) const {
  * Set the maximum backup to 'backup', in response to a pragma
  * statement.
  */
-void TransliteratorParser::pragmaMaximumBackup(int32_t backup) {
+void TransliteratorParser::pragmaMaximumBackup(int32_t /*backup*/) {
     //TODO Finish
 }
 
@@ -1101,7 +1101,7 @@ void TransliteratorParser::pragmaMaximumBackup(int32_t backup) {
  * Begin normalizing all rules using the given mode, in response
  * to a pragma statement.
  */
-void TransliteratorParser::pragmaNormalizeRules(UNormalizationMode mode) {
+void TransliteratorParser::pragmaNormalizeRules(UNormalizationMode /*mode*/) {
     //TODO Finish
 }