diff --git a/rc/cpp.kak b/rc/cpp.kak
index 3edbd535..0208a08d 100644
--- a/rc/cpp.kak
+++ b/rc/cpp.kak
@@ -36,7 +36,7 @@ def -hidden _cpp_indent_on_closing_curly_brace %[
     # align to opening curly brace when alone on a line
     try %[ exec -itersel -draft <a-h><a-k>^\h+\}$<ret>hms\`|.\'<ret>1<a-&> ]
     # add ; after } if class or struct definition
-    try %[ exec -draft "hm<space><a-?>(class|struct)<ret><a-k>\`(class|struct)[^{}\n]+(\n)?\s*\{\'<ret><a-space>ma;<esc>" ]
+    try %[ exec -draft "hm<space><a-?>(class|struct|union)<ret><a-k>\`(class|struct|union)[^{}\n]+(\n)?\s*\{\'<ret><a-space>ma;<esc>" ]
 ]
 
 addhl -group / regions -default code cpp \