diff --git a/ext/dapr-ext-workflow/setup.cfg b/ext/dapr-ext-workflow/setup.cfg
index 3776ec89..ec745c5c 100644
--- a/ext/dapr-ext-workflow/setup.cfg
+++ b/ext/dapr-ext-workflow/setup.cfg
@@ -27,6 +27,11 @@ install_requires =
     dapr-dev >= 1.15.0.dev
     durabletask-dapr >= 0.2.0a7
 
+    # protobuf dependency constrained per durabletask grpc generator
+    # in https://github.com/dapr/durabletask-python/blob/main/dev-requirements.txt
+    # check install_requires in https://github.com/grpc/grpc/blob/master/tools/distrib/python/grpcio_tools/setup.py#L349
+    protobuf>=6.31.0,<7.0.0
+
 [options.packages.find]
 include =
     dapr.*