diff --git a/lib/includes/nghttp2/nghttp2.h b/lib/includes/nghttp2/nghttp2.h
index 94b07753..47ca79a5 100644
--- a/lib/includes/nghttp2/nghttp2.h
+++ b/lib/includes/nghttp2/nghttp2.h
@@ -2879,8 +2879,8 @@ NGHTTP2_EXTERN int nghttp2_session_consume_stream(nghttp2_session *session,
  * :enum:`NGHTTP2_ERR_NOMEM`
  *     Out of memory.
  * :enum:`NGHTTP2_ERR_INVALID_ARGUMENT`
- *     Attempted to depend on itself; no stream exist for the given
- *     |stream_id|.
+ *     Attempted to depend on itself; or no stream exist for the given
+ *     |stream_id|; or |stream_id| is 0
  */
 NGHTTP2_EXTERN int
 nghttp2_session_change_stream_priority(nghttp2_session *session,
diff --git a/lib/nghttp2_session.c b/lib/nghttp2_session.c
index 7f1e883e..473b3807 100644
--- a/lib/nghttp2_session.c
+++ b/lib/nghttp2_session.c
@@ -6789,7 +6789,7 @@ int nghttp2_session_change_stream_priority(
   nghttp2_stream *stream;
   nghttp2_priority_spec pri_spec_copy;
 
-  if (stream_id == pri_spec->stream_id) {
+  if (stream_id == 0 || stream_id == pri_spec->stream_id) {
     return NGHTTP2_ERR_INVALID_ARGUMENT;
   }
 
diff --git a/tests/nghttp2_session_test.c b/tests/nghttp2_session_test.c
index 3b85e743..45f61d33 100644
--- a/tests/nghttp2_session_test.c
+++ b/tests/nghttp2_session_test.c
@@ -8379,6 +8379,10 @@ void test_nghttp2_session_change_stream_priority(void) {
   rv = nghttp2_session_change_stream_priority(session, 1, &pri_spec);
   CU_ASSERT(NGHTTP2_ERR_INVALID_ARGUMENT == rv);
 
+  /* It is an error to change priority of root stream (0) */
+  rv = nghttp2_session_change_stream_priority(session, 0, &pri_spec);
+  CU_ASSERT(NGHTTP2_ERR_INVALID_ARGUMENT == rv);
+
   nghttp2_session_del(session);
 }