diff --git a/moto/awslambda/responses.py b/moto/awslambda/responses.py
index 73f969890..6f4f76c0f 100644
--- a/moto/awslambda/responses.py
+++ b/moto/awslambda/responses.py
@@ -37,8 +37,7 @@ class LambdaResponse(BaseResponse):
 
     def _create_function(self, request, full_url, headers):
         lambda_backend = self.get_lambda_backend(full_url)
-
-        spec = json.loads(request.body)
+        spec = json.loads(request.body.decode('utf-8'))
         try:
             fn = lambda_backend.create_function(spec)
         except ValueError as e: