diff --git a/include/mshtmdid.h b/include/mshtmdid.h
index 67d4835a0d2..01a2f5ab262 100644
--- a/include/mshtmdid.h
+++ b/include/mshtmdid.h
@@ -4119,6 +4119,10 @@
 #define DISPID_IDOMKEYBOARDEVENT_IE9_CHAR           DISPID_DOMKEYBOARDEVENT+13
 #define DISPID_IDOMKEYBOARDEVENT_LOCALE             DISPID_DOMKEYBOARDEVENT+14
 
+/* IDOMCustomEvent */
+#define DISPID_IDOMCUSTOMEVENT_DETAIL           DISPID_DOMCUSTOMEVENT+1
+#define DISPID_IDOMCUSTOMEVENT_INITCUSTOMEVENT  DISPID_DOMCUSTOMEVENT+2
+
 /* IDOMMessageEvent */
 #define DISPID_IDOMMESSAGEEVENT_DATA              DISPID_DOMMESSAGEEVENT+1
 #define DISPID_IDOMMESSAGEEVENT_ORIGIN            DISPID_DOMMESSAGEEVENT+2
diff --git a/include/mshtml.idl b/include/mshtml.idl
index 800fe38d41b..b92955c6cc9 100644
--- a/include/mshtml.idl
+++ b/include/mshtml.idl
@@ -23640,6 +23640,52 @@ methods:
     BSTR locale();
 }
 
+/*****************************************************************************
+ *    IDOMCustomEvent interface
+ */
+[
+    odl,
+    oleautomation,
+    dual,
+    uuid(305106de-98b5-11cf-bb82-00aa00bdce0b)
+]
+interface IDOMCustomEvent : IDispatch
+{
+    [propget, id(DISPID_IDOMCUSTOMEVENT_DETAIL)]
+    HRESULT detail([out, retval] VARIANT *p);
+
+    [id(DISPID_IDOMCUSTOMEVENT_INITCUSTOMEVENT)]
+    HRESULT initCustomEvent(
+            [in] BSTR eventType,
+            [in] VARIANT_BOOL canBubble,
+            [in] VARIANT_BOOL cancelable,
+            [in] VARIANT *detail);
+}
+
+/*****************************************************************************
+ *    DispDOMCustomEvent dispinterface
+ */
+[
+    hidden,
+    uuid(3059007c-98b5-11cf-bb82-00aa00bdce0b)
+]
+dispinterface DispDOMCustomEvent
+{
+properties:
+methods:
+    WINE_IDOMEVENT_DISPINTERFACE_DECL;
+
+    [propget, id(DISPID_IDOMCUSTOMEVENT_DETAIL)]
+    VARIANT detail();
+
+    [id(DISPID_IDOMCUSTOMEVENT_INITCUSTOMEVENT)]
+    void initCustomEvent(
+            [in] BSTR eventType,
+            [in] VARIANT_BOOL canBubble,
+            [in] VARIANT_BOOL cancelable,
+            [in] VARIANT *detail);
+}
+
 /*****************************************************************************
  *    IDOMMessageEvent interface
  */