diff --git a/pstl/include/pstl/internal/omp/parallel_reduce.h b/pstl/include/pstl/internal/omp/parallel_reduce.h
--- a/pstl/include/pstl/internal/omp/parallel_reduce.h
+++ b/pstl/include/pstl/internal/omp/parallel_reduce.h
@@ -23,6 +23,11 @@
 __parallel_reduce_body(_RandomAccessIterator __first, _RandomAccessIterator __last, _Value __identity,
                        _RealBody __real_body, _Reduction __reduce)
 {
+    if (__should_run_serial(__first, __last))
+    {
+        return __real_body(__first, __last, __identity);
+    }
+
     auto __middle = __first + ((__last - __first) / 2);
     _Value __v1(__identity), __v2(__identity);
     __parallel_invoke_body(