diff --git a/packages/language-c/grammars/tree-sitter-c/highlights.scm b/packages/language-c/grammars/tree-sitter-c/highlights.scm
index 096c75956..344340d1e 100644
--- a/packages/language-c/grammars/tree-sitter-c/highlights.scm
+++ b/packages/language-c/grammars/tree-sitter-c/highlights.scm
@@ -305,7 +305,7 @@
 ; macro preprocessors. The convention is decently strong in C/C++ that all-caps
 ; identifiers will refer to `#define`d things.
 ((identifier) @constant.other.c
-  (#match? @constant.other.c "[_A-Z][_A-Z0-9]*$")
+  (#match? @constant.other.c "^[_A-Z][_A-Z0-9]*$")
   (#set! capture.shy))