diff --git a/dlls/avrt/avrt.spec b/dlls/avrt/avrt.spec
index 103798d733c..a253d9a4a18 100644
--- a/dlls/avrt/avrt.spec
+++ b/dlls/avrt/avrt.spec
@@ -1,5 +1,5 @@
 @ stub AvQuerySystemResponsiveness
-@ stub AvRevertMmThreadCharacteristics
+@ stdcall AvRevertMmThreadCharacteristics(long)
 @ stub AvRtCreateThreadOrderingGroup
 @ stub AvRtCreateThreadOrderingGroupExA
 @ stub AvRtCreateThreadOrderingGroupExW
@@ -9,6 +9,6 @@
 @ stub AvRtWaitOnThreadOrderingGroup
 @ stub AvSetMmMaxThreadCharacteristicsA
 @ stub AvSetMmMaxThreadCharacteristicsW
-@ stub AvSetMmThreadCharacteristicsA
-@ stub AvSetMmThreadCharacteristicsW
+@ stdcall AvSetMmThreadCharacteristicsA(str ptr)
+@ stdcall AvSetMmThreadCharacteristicsW(wstr ptr)
 @ stub AvSetMmThreadPriority
diff --git a/dlls/avrt/main.c b/dlls/avrt/main.c
index a39743c6a6e..c4e53dd2d76 100644
--- a/dlls/avrt/main.c
+++ b/dlls/avrt/main.c
@@ -23,6 +23,7 @@
 
 #include "windef.h"
 #include "winbase.h"
+#include "winnls.h"
 #include "wine/debug.h"
 #include "avrt.h"
 
@@ -45,3 +46,47 @@ BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReserved)
 
     return TRUE;
 }
+
+HANDLE WINAPI AvSetMmThreadCharacteristicsA(LPCSTR TaskName, LPDWORD TaskIndex)
+{
+    HANDLE ret;
+    LPWSTR str = NULL;
+
+    if (TaskName)
+    {
+        DWORD len = (lstrlenA(TaskName)+1);
+        str = HeapAlloc(GetProcessHeap, 0, len*sizeof(WCHAR));
+        if (!str)
+        {
+            SetLastError(ERROR_OUTOFMEMORY);
+            return NULL;
+        }
+        MultiByteToWideChar(CP_ACP, 0, TaskName, len, str, len);
+    }
+    ret = AvSetMmThreadCharacteristicsW(str, TaskIndex);
+    HeapFree(GetProcessHeap(), 0, str);
+    return ret;
+}
+
+HANDLE WINAPI AvSetMmThreadCharacteristicsW(LPCWSTR TaskName, LPDWORD TaskIndex)
+{
+    FIXME("(%s,%p): stub\n", debugstr_w(TaskName), TaskIndex);
+
+    if (!TaskName)
+    {
+        SetLastError(ERROR_INVALID_TASK_NAME);
+        return NULL;
+    }
+    if (!TaskIndex)
+    {
+        SetLastError(ERROR_INVALID_HANDLE);
+        return NULL;
+    }
+    return (HANDLE)0x12345678;
+}
+
+BOOL WINAPI AvRevertMmThreadCharacteristics(HANDLE AvrtHandle)
+{
+    FIXME("(%p): stub\n", AvrtHandle);
+    return 1;
+}