diff --git a/dlls/ole32/compobj.c b/dlls/ole32/compobj.c
index a920b9c..ad8795a 100644
--- a/dlls/ole32/compobj.c
+++ b/dlls/ole32/compobj.c
@@ -3353,10 +3353,71 @@ HRESULT WINAPI CoCopyProxy(IUnknown *pProxy, IUnknown **ppCopy)
  */
 HRESULT WINAPI CoGetCallContext(REFIID riid, void **ppv)
 {
-    FIXME("(%s, %p): stub\n", debugstr_guid(riid), ppv);
+    struct oletls * info;
+    HRESULT hr;
 
-    *ppv = NULL;
-    return E_NOINTERFACE;
+    TRACE("(%s, %p)\n", debugstr_guid(riid), ppv);
+    if( !ppv)
+        return E_INVALIDARG;
+
+    /* get COM tls */
+    info = COM_CurrentInfo();
+    if( !info)
+        return E_OUTOFMEMORY;
+
+    hr = RPC_E_CALL_COMPLETE;
+    if( info->ctx_call)
+    {
+        hr = IUnknown_QueryInterface( info->ctx_call, riid, ppv);
+    }
+
+    if (FAILED(hr))
+    {
+        ERR("call context QI(%p), hr=0x%08x\n", info->ctx_call, hr);
+        *ppv = NULL;
+        return hr;
+    }
+
+    TRACE("call context QI(%p) -> %p\n", info->ctx_call, *ppv);
+    return hr;
+}
+
+/***********************************************************************
+ *           CoSwitchCallContext [OLE32.@]
+ *
+ * Switches the call context object used by CoGetCallContext.
+ *
+ * PARAMS
+ *  pNewObject  [I] A pointer to an interface on the new call context object.
+ *  ppOldObject [O] Address of pointer variable that receives a pointer to the
+ *                  call context object of the call currently in progress
+ *
+ * RETURNS
+ *  Success: S_OK.
+ *  Failure: HRESULT code.
+ */
+HRESULT WINAPI CoSwitchCallContext(IUnknown *pNewObject,IUnknown **ppOldObject)
+{
+    struct oletls * info;
+
+    TRACE("(%p)\n", pNewObject);
+
+    /* get COM tls */
+    info = COM_CurrentInfo();
+    if( !info)
+        return E_OUTOFMEMORY;
+
+    /* Receives a pointer to the call context object of the call currently
+       in progress. This value is returned so that the original call context
+       can be restored by the custom marshaller.
+       The returned pointer will be NULL if there was no call in progress. */
+    *ppOldObject = info->ctx_call;
+
+    /* It may be NULL if you are calling CoSwitchCallContext to switch back
+       to the original call context and there was no original call context. */
+    info->ctx_call = pNewObject;
+
+    return S_OK;
 }
 
 /***********************************************************************
diff --git a/dlls/ole32/compobj_private.h b/dlls/ole32/compobj_private.h
index 4b88ad2..505036d 100644
--- a/dlls/ole32/compobj_private.h
+++ b/dlls/ole32/compobj_private.h
@@ -181,6 +181,7 @@ struct oletls
     GUID             causality_id; /* unique identifier for each COM call */
     LONG             pending_call_count_client; /* number of client calls pending */
     LONG             pending_call_count_server; /* number of server calls pending */
+    IUnknown         *ctx_call;    /* call context */
 };
 
 
diff --git a/dlls/ole32/ole32.spec b/dlls/ole32/ole32.spec
index 79376ac..b9a795c 100644
--- a/dlls/ole32/ole32.spec
+++ b/dlls/ole32/ole32.spec
@@ -73,7 +73,7 @@
 @ stdcall CoSetProxyBlanket(ptr long long wstr long long ptr long)
 @ stdcall CoSetState(ptr)
 @ stdcall CoSuspendClassObjects()
-@ stub CoSwitchCallContext
+@ stdcall CoSwitchCallContext(ptr ptr)
 @ stdcall CoTaskMemAlloc(long)
 @ stdcall CoTaskMemFree(ptr)
 @ stdcall CoTaskMemRealloc(ptr long)