diff --git a/.clang-format b/.clang-format
index 024d10a..0bf524f 100644
--- a/.clang-format
+++ b/.clang-format
@@ -16,7 +16,7 @@ EmptyLineBeforeAccessModifier: Never
 FixNamespaceComments: false
 IncludeBlocks: Regroup
 IncludeCategories:
-  - Regex: "<[a-z]*>"
+  - Regex: "<[a-z_]*>"
     Priority: 1
   - Regex: "<catch2\/.*>"
     Priority: 2