diff --git a/runtime/queries/rbs/highlights.scm b/runtime/queries/rbs/highlights.scm
index b44dcda95..a57ac2def 100644
--- a/runtime/queries/rbs/highlights.scm
+++ b/runtime/queries/rbs/highlights.scm
@@ -171,6 +171,7 @@
 [
   ","
   "."
+  ":"
 ] @punctuation.delimiter
 
 ; RBS Inline prefix (keep comment color)