diff --git a/expat/apply-clang-tidy.sh b/expat/apply-clang-tidy.sh
index b8a7f118..a17d823f 100755
--- a/expat/apply-clang-tidy.sh
+++ b/expat/apply-clang-tidy.sh
@@ -33,6 +33,7 @@ set -e -u -o pipefail
 cd "$(dirname "$(type -P "$0")")"
 
 checks_to_enable=(
+    bugprone-narrowing-conversions
     bugprone-suspicious-string-compare
     readability-avoid-const-params-in-decls
     readability-named-parameter