diff --git a/src/reflect/value.go b/src/reflect/value.go
index 650da5b02d2627..f441fe92d9f5cd 100644
--- a/src/reflect/value.go
+++ b/src/reflect/value.go
@@ -1683,6 +1683,9 @@ func (it *MapIter) SetValue(dst Value) {
 // entry. It returns false when the iterator is exhausted; subsequent
 // calls to Key, Value, or Next will panic.
 func (it *MapIter) Next() bool {
+	if !it.m.IsValid() {
+		panic("MapIter.Next called on an iterator that does not have an associated map Value")
+	}
 	if it.it == nil {
 		it.it = unsafe.Pointer(&it.hiter)
 		mapiterinit(it.m.typ, it.m.pointer(), it.it)