diff --git a/dlls/mshtml/htmldoc.c b/dlls/mshtml/htmldoc.c
index 4e56d548f47..54273f5a6e0 100644
--- a/dlls/mshtml/htmldoc.c
+++ b/dlls/mshtml/htmldoc.c
@@ -2637,7 +2637,8 @@ static HRESULT WINAPI HTMLDocument4_get_namespaces(IHTMLDocument4 *iface, IDispa
     if(!This->doc_node->namespaces) {
         HRESULT hres;
 
-        hres = create_namespace_collection(&This->doc_node->namespaces);
+        hres = create_namespace_collection(dispex_compat_mode(&This->doc_node->node.event_target.dispex),
+                                           &This->doc_node->namespaces);
         if(FAILED(hres))
             return hres;
     }
diff --git a/dlls/mshtml/mshtml_private.h b/dlls/mshtml/mshtml_private.h
index 03aa7e33b16..be19d98637f 100644
--- a/dlls/mshtml/mshtml_private.h
+++ b/dlls/mshtml/mshtml_private.h
@@ -915,7 +915,7 @@ HRESULT create_navigator(compat_mode_t,IOmNavigator**) DECLSPEC_HIDDEN;
 HRESULT create_html_screen(compat_mode_t,IHTMLScreen**) DECLSPEC_HIDDEN;
 HRESULT create_performance(compat_mode_t,IHTMLPerformance**) DECLSPEC_HIDDEN;
 HRESULT create_history(HTMLInnerWindow*,OmHistory**) DECLSPEC_HIDDEN;
-HRESULT create_namespace_collection(IHTMLNamespaceCollection**) DECLSPEC_HIDDEN;
+HRESULT create_namespace_collection(compat_mode_t,IHTMLNamespaceCollection**) DECLSPEC_HIDDEN;
 HRESULT create_dom_implementation(HTMLDocumentNode*,IHTMLDOMImplementation**) DECLSPEC_HIDDEN;
 void detach_dom_implementation(IHTMLDOMImplementation*) DECLSPEC_HIDDEN;
 
diff --git a/dlls/mshtml/omnavigator.c b/dlls/mshtml/omnavigator.c
index e43328bf5b2..e55753a83d9 100644
--- a/dlls/mshtml/omnavigator.c
+++ b/dlls/mshtml/omnavigator.c
@@ -2330,7 +2330,7 @@ static dispex_static_data_t HTMLNamespaceCollection_dispex = {
     HTMLNamespaceCollection_iface_tids
 };
 
-HRESULT create_namespace_collection(IHTMLNamespaceCollection **ret)
+HRESULT create_namespace_collection(compat_mode_t compat_mode, IHTMLNamespaceCollection **ret)
 {
     HTMLNamespaceCollection *namespaces;
 
@@ -2339,7 +2339,8 @@ HRESULT create_namespace_collection(IHTMLNamespaceCollection **ret)
 
     namespaces->IHTMLNamespaceCollection_iface.lpVtbl = &HTMLNamespaceCollectionVtbl;
     namespaces->ref = 1;
-    init_dispex(&namespaces->dispex, (IUnknown*)&namespaces->IHTMLNamespaceCollection_iface, &HTMLNamespaceCollection_dispex);
+    init_dispex_with_compat_mode(&namespaces->dispex, (IUnknown*)&namespaces->IHTMLNamespaceCollection_iface,
+                                 &HTMLNamespaceCollection_dispex, compat_mode);
     *ret = &namespaces->IHTMLNamespaceCollection_iface;
     return S_OK;
 }