diff --git a/blueprintcompiler/language/imports.py b/blueprintcompiler/language/imports.py
index 4fac192..823baec 100644
--- a/blueprintcompiler/language/imports.py
+++ b/blueprintcompiler/language/imports.py
@@ -57,7 +57,8 @@ class GtkDirective(AstNode):
         # validate the GTK version first to make sure the more specific error
         # message is emitted
         self.gtk_version()
-        return gir.get_namespace("Gtk", self.tokens["version"])
+        if self.tokens["version"] is not None:
+            return gir.get_namespace("Gtk", self.tokens["version"])
 
 
     def emit_xml(self, xml: XmlEmitter):
diff --git a/blueprintcompiler/language/ui.py b/blueprintcompiler/language/ui.py
index c1adbde..e0d5dcd 100644
--- a/blueprintcompiler/language/ui.py
+++ b/blueprintcompiler/language/ui.py
@@ -45,7 +45,8 @@ class UI(AstNode):
         self._gir_errors = []
 
         try:
-            gir_ctx.add_namespace(self.children[GtkDirective][0].gir_namespace)
+            if gtk := self.children[GtkDirective][0].gir_namespace:
+                gir_ctx.add_namespace(gtk)
         except CompileError as e:
             self._gir_errors.append(e)