diff --git a/dlls/kernelbase/kernelbase.spec b/dlls/kernelbase/kernelbase.spec
index e1fb19eceb0..dd9f4a8ddce 100644
--- a/dlls/kernelbase/kernelbase.spec
+++ b/dlls/kernelbase/kernelbase.spec
@@ -1460,7 +1460,7 @@
 @ stdcall SetPrivateObjectSecurityEx(long ptr ptr long ptr long)
 @ stdcall SetProcessAffinityUpdateMode(long long)
 # @ stub SetProcessDefaultCpuSets
-# @ stub SetProcessGroupAffinity
+@ stdcall SetProcessGroupAffinity(long ptr ptr)
 # @ stub SetProcessInformation
 @ stdcall SetProcessMitigationPolicy(long ptr long)
 @ stdcall SetProcessPreferredUILanguages(long ptr ptr)
diff --git a/dlls/kernelbase/process.c b/dlls/kernelbase/process.c
index 101d3fa3213..5973eb7d933 100644
--- a/dlls/kernelbase/process.c
+++ b/dlls/kernelbase/process.c
@@ -1133,6 +1133,18 @@ BOOL WINAPI DECLSPEC_HOTPATCH SetProcessAffinityUpdateMode( HANDLE process, DWOR
 }
 
 
+/***********************************************************************
+ *           SetProcessGroupAffinity   (kernelbase.@)
+ */
+BOOL WINAPI DECLSPEC_HOTPATCH SetProcessGroupAffinity( HANDLE process, const GROUP_AFFINITY *new,
+                                                       GROUP_AFFINITY *old )
+{
+    FIXME( "(%p,%p,%p): stub\n", process, new, old );
+    SetLastError( ERROR_CALL_NOT_IMPLEMENTED );
+    return FALSE;
+}
+
+
 /**********************************************************************
  *           SetProcessMitigationPolicy   (kernelbase.@)
  */