diff --git a/SystemDoc.md b/SystemDoc.md
index b710d03f..7d578b91 100644
--- a/SystemDoc.md
+++ b/SystemDoc.md
@@ -39,3 +39,5 @@ Selected Subsystems Documentation
 
 -   [InterVM file copy (used by DisposableVMs)](/wiki/Qfilecopy)
 
+-   [Qubes GUI protocol](/wiki/GUIdocs)
+