diff --git a/buf/registry/module/v1beta1/upload_service.proto b/buf/registry/module/v1beta1/upload_service.proto
index 8c35b81..100bed9 100644
--- a/buf/registry/module/v1beta1/upload_service.proto
+++ b/buf/registry/module/v1beta1/upload_service.proto
@@ -86,7 +86,10 @@ message UploadRequest {
   //
   // Commits should be unique by Module, that is no two dep_commit_ids should have the same Module but
   // different Commit IDs.
-  repeated string dep_commit_ids = 2 [(buf.validate.field).repeated.items.string.uuid = true];
+  repeated string dep_commit_ids = 2 [
+    (buf.validate.field).repeated.unique = true,
+    (buf.validate.field).repeated.items.string.uuid = true
+  ];
 }
 
 message UploadResponse {