diff --git a/src/sagemaker_server.cc b/src/sagemaker_server.cc
index 49b8a3ba06..0e6dce5ce2 100644
--- a/src/sagemaker_server.cc
+++ b/src/sagemaker_server.cc
@@ -646,6 +646,7 @@ SagemakerAPIServer::SageMakerMMEUnloadModel(
     target_model = model_name_hash;
   }
 
+  std::lock_guard<std::mutex> lock(models_list_mutex_);
   if (sagemaker_models_list_.find(model_name_hash) ==
       sagemaker_models_list_.end()) {
     LOG_VERBOSE(1) << "Model " << target_model << " with model hash "
@@ -740,7 +741,6 @@ SagemakerAPIServer::SageMakerMMEUnloadModel(
 
   TRITONSERVER_ErrorDelete(unregister_err);
 
-  std::lock_guard<std::mutex> lock(models_list_mutex_);
   sagemaker_models_list_.erase(model_name_hash);
 }