diff --git a/blueprintcompiler/completions.py b/blueprintcompiler/completions.py
index 0a5e759..e030961 100644
--- a/blueprintcompiler/completions.py
+++ b/blueprintcompiler/completions.py
@@ -93,6 +93,17 @@ def object_completer(ast_node, match_variables):
             yield Completion(c.name, CompletionItemKind.Class, docs=c.doc)
 
 
+@completer(
+    applies_in=[language.UI, language.ObjectContent, language.Template],
+    matches=new_statement_patterns,
+)
+def gtk_object_completer(ast_node, match_variables):
+    ns = ast_node.root.gir.namespaces.get("Gtk")
+    if ns is not None:
+        for c in ns.classes.values():
+            yield Completion(c.name, CompletionItemKind.Class, docs=c.doc)
+
+
 @completer(
     applies_in=[language.ObjectContent],
     matches=new_statement_patterns,