diff --git a/crates/zed/src/languages/php/highlights.scm b/crates/zed/src/languages/php/highlights.scm
index fcb087c47d14dbc036ed79a50be7ff1b57ebc4e8..5f366b53c3b950f4a9a9b8fec639272aef02a558 100644
--- a/crates/zed/src/languages/php/highlights.scm
+++ b/crates/zed/src/languages/php/highlights.scm
@@ -96,6 +96,7 @@
 "endwhile" @keyword
 "extends" @keyword
 "final" @keyword
+"readonly" @keyword
 "finally" @keyword
 "foreach" @keyword
 "function" @keyword