diff --git a/Userland/Libraries/LibWeb/WebIDL/Promise.h b/Userland/Libraries/LibWeb/WebIDL/Promise.h
index 37c8f1e14c..7e0e8141c8 100644
--- a/Userland/Libraries/LibWeb/WebIDL/Promise.h
+++ b/Userland/Libraries/LibWeb/WebIDL/Promise.h
@@ -8,6 +8,7 @@
 #pragma once
 
 #include <LibJS/Forward.h>
+#include <LibJS/Runtime/PromiseCapability.h>
 #include <LibJS/Runtime/Value.h>
 #include <LibJS/SafeFunction.h>
 #include <LibWeb/Forward.h>