diff --git a/google/cloud/bigquery/client.py b/google/cloud/bigquery/client.py
index a5f3d5419..161273094 100644
--- a/google/cloud/bigquery/client.py
+++ b/google/cloud/bigquery/client.py
@@ -4127,7 +4127,7 @@ def _get_upload_headers(user_agent):
         "Accept": "application/json",
         "Accept-Encoding": "gzip, deflate",
         "User-Agent": user_agent,
-        "content-type": "application/json",
+        "content-type": "application/json; charset=UTF-8",
     }