diff --git a/storages/backends/gcloud.py b/storages/backends/gcloud.py
index 9c7d1574f..730476b8d 100644
--- a/storages/backends/gcloud.py
+++ b/storages/backends/gcloud.py
@@ -69,7 +69,7 @@ def read(self, num_bytes=None):
         return super(GoogleCloudFile, self).read(num_bytes)
 
     def write(self, content):
-        if 'w' not in self._mode:
+        if 'w' not in self._mode and 'r+' not in self._mode:
             raise AttributeError("File was not opened in write mode.")
         self._is_dirty = True
         return super(GoogleCloudFile, self).write(force_bytes(content))