diff --git a/dlls/ntdll/ntdll.spec b/dlls/ntdll/ntdll.spec
index 38422ae39a8..464b23323dd 100644
--- a/dlls/ntdll/ntdll.spec
+++ b/dlls/ntdll/ntdll.spec
@@ -213,6 +213,7 @@
 @ stdcall NtOpenIoCompletion(ptr long ptr)
 @ stdcall NtOpenJobObject(ptr long ptr)
 @ stdcall NtOpenKey(ptr long ptr)
+@ stdcall NtOpenKeyEx(ptr long ptr long)
 @ stdcall NtOpenKeyedEvent(ptr long ptr)
 @ stdcall NtOpenMutant(ptr long ptr)
 @ stub NtOpenObjectAuditAlarm
@@ -1128,6 +1129,7 @@
 @ stdcall ZwOpenIoCompletion(ptr long ptr) NtOpenIoCompletion
 @ stdcall ZwOpenJobObject(ptr long ptr) NtOpenJobObject
 @ stdcall ZwOpenKey(ptr long ptr) NtOpenKey
+@ stdcall ZwOpenKeyEx(ptr long ptr long) NtOpenKeyEx
 @ stdcall ZwOpenKeyedEvent(ptr long ptr) NtOpenKeyedEvent
 @ stdcall ZwOpenMutant(ptr long ptr) NtOpenMutant
 @ stub ZwOpenObjectAuditAlarm
diff --git a/dlls/ntdll/reg.c b/dlls/ntdll/reg.c
index a104c2e9cb9..c0fc64120a5 100644
--- a/dlls/ntdll/reg.c
+++ b/dlls/ntdll/reg.c
@@ -106,14 +106,10 @@ NTSTATUS WINAPI RtlpNtCreateKey( PHANDLE retkey, ACCESS_MASK access, const OBJEC
 }
 
 /******************************************************************************
- * NtOpenKey [NTDLL.@]
- * ZwOpenKey [NTDLL.@]
- *
- *   OUT	HANDLE			retkey (returns 0 when failure)
- *   IN		ACCESS_MASK		access
- *   IN		POBJECT_ATTRIBUTES 	attr
+ * NtOpenKeyEx [NTDLL.@]
+ * ZwOpenKeyEx [NTDLL.@]
  */
-NTSTATUS WINAPI NtOpenKey( PHANDLE retkey, ACCESS_MASK access, const OBJECT_ATTRIBUTES *attr )
+NTSTATUS WINAPI NtOpenKeyEx( PHANDLE retkey, ACCESS_MASK access, const OBJECT_ATTRIBUTES *attr, ULONG options )
 {
     NTSTATUS ret;
     DWORD len;
@@ -123,6 +119,8 @@ NTSTATUS WINAPI NtOpenKey( PHANDLE retkey, ACCESS_MASK access, const OBJECT_ATTR
     len = attr->ObjectName->Length;
     TRACE( "(%p,%s,%x,%p)\n", attr->RootDirectory,
            debugstr_us(attr->ObjectName), access, retkey );
+    if (options)
+        FIXME("options %x not implemented\n", options);
 
     if (len > MAX_NAME_LENGTH) return STATUS_BUFFER_OVERFLOW;
 
@@ -140,6 +138,19 @@ NTSTATUS WINAPI NtOpenKey( PHANDLE retkey, ACCESS_MASK access, const OBJECT_ATTR
     return ret;
 }
 
+/******************************************************************************
+ * NtOpenKey [NTDLL.@]
+ * ZwOpenKey [NTDLL.@]
+ *
+ *   OUT	HANDLE			retkey (returns 0 when failure)
+ *   IN		ACCESS_MASK		access
+ *   IN		POBJECT_ATTRIBUTES 	attr
+ */
+NTSTATUS WINAPI NtOpenKey( PHANDLE retkey, ACCESS_MASK access, const OBJECT_ATTRIBUTES *attr )
+{
+    return NtOpenKeyEx( retkey, access, attr, 0 );
+}
+
 /******************************************************************************
  * RtlpNtOpenKey [NTDLL.@]
  *
diff --git a/dlls/ntdll/tests/reg.c b/dlls/ntdll/tests/reg.c
index 6d04668539c..ecfe1b24f78 100644
--- a/dlls/ntdll/tests/reg.c
+++ b/dlls/ntdll/tests/reg.c
@@ -123,6 +123,7 @@ static NTSTATUS (WINAPI * pRtlQueryRegistryValues)(IN ULONG, IN PCWSTR,IN PRTL_Q
 static NTSTATUS (WINAPI * pRtlCheckRegistryKey)(IN ULONG,IN PWSTR);
 static NTSTATUS (WINAPI * pRtlOpenCurrentUser)(IN ACCESS_MASK, PHANDLE);
 static NTSTATUS (WINAPI * pNtOpenKey)(PHANDLE, IN ACCESS_MASK, IN POBJECT_ATTRIBUTES);
+static NTSTATUS (WINAPI * pNtOpenKeyEx)(PHANDLE, ACCESS_MASK, POBJECT_ATTRIBUTES, ULONG);
 static NTSTATUS (WINAPI * pNtClose)(IN HANDLE);
 static NTSTATUS (WINAPI * pNtFlushKey)(HANDLE);
 static NTSTATUS (WINAPI * pNtDeleteKey)(HANDLE);
@@ -195,6 +196,7 @@ static BOOL InitFunctionPtrs(void)
 
     /* optional functions */
     pNtQueryLicenseValue = (void *)GetProcAddress(hntdll, "NtQueryLicenseValue");
+    pNtOpenKeyEx = (void *)GetProcAddress(hntdll, "NtOpenKeyEx");
 
     return TRUE;
 }
@@ -351,6 +353,18 @@ static void test_NtOpenKey(void)
     attr.Length *= 2;
     status = pNtOpenKey(&key, am, &attr);
     ok(status == STATUS_INVALID_PARAMETER, "Expected STATUS_INVALID_PARAMETER, got: 0x%08x\n", status);
+
+    if (!pNtOpenKeyEx)
+    {
+        win_skip("NtOpenKeyEx not available\n");
+        return;
+    }
+
+    InitializeObjectAttributes(&attr, &winetestpath, 0, 0, 0);
+    status = pNtOpenKeyEx(&key, KEY_WRITE|KEY_READ, &attr, 0);
+    ok(status == STATUS_SUCCESS, "NtOpenKeyEx Failed: 0x%08x\n", status);
+
+    pNtClose(key);
 }
 
 static void test_NtCreateKey(void)
diff --git a/include/winternl.h b/include/winternl.h
index 54203913674..f3de6363ef6 100644
--- a/include/winternl.h
+++ b/include/winternl.h
@@ -2169,6 +2169,7 @@ NTSYSAPI NTSTATUS  WINAPI NtOpenFile(PHANDLE,ACCESS_MASK,POBJECT_ATTRIBUTES,PIO_
 NTSYSAPI NTSTATUS  WINAPI NtOpenIoCompletion(PHANDLE,ACCESS_MASK,POBJECT_ATTRIBUTES);
 NTSYSAPI NTSTATUS  WINAPI NtOpenJobObject(PHANDLE,ACCESS_MASK,const OBJECT_ATTRIBUTES*);
 NTSYSAPI NTSTATUS  WINAPI NtOpenKey(PHANDLE,ACCESS_MASK,const OBJECT_ATTRIBUTES *);
+NTSYSAPI NTSTATUS  WINAPI NtOpenKeyEx(PHANDLE,ACCESS_MASK,const OBJECT_ATTRIBUTES*,ULONG);
 NTSYSAPI NTSTATUS  WINAPI NtOpenKeyedEvent(HANDLE*,ACCESS_MASK,const OBJECT_ATTRIBUTES*);
 NTSYSAPI NTSTATUS  WINAPI NtOpenMutant(PHANDLE,ACCESS_MASK,const OBJECT_ATTRIBUTES*);
 NTSYSAPI NTSTATUS  WINAPI NtOpenObjectAuditAlarm(PUNICODE_STRING,PHANDLE,PUNICODE_STRING,PUNICODE_STRING,PSECURITY_DESCRIPTOR,HANDLE,ACCESS_MASK,ACCESS_MASK,PPRIVILEGE_SET,BOOLEAN,BOOLEAN,PBOOLEAN);