diff --git a/docs/topics/media-pipeline.rst b/docs/topics/media-pipeline.rst
index 41beebe98..a1f518cbd 100644
--- a/docs/topics/media-pipeline.rst
+++ b/docs/topics/media-pipeline.rst
@@ -189,6 +189,8 @@ Google Cloud Storage
 ---------------------
 
 .. setting:: GCS_PROJECT_ID
+.. setting:: FILES_STORE_GCS_ACL
+.. setting:: IMAGES_STORE_GCS_ACL
 
 :setting:`FILES_STORE` and :setting:`IMAGES_STORE` can represent a Google Cloud Storage
 bucket. Scrapy will automatically upload the files to the bucket. (requires `google-cloud-storage`_ )
@@ -204,6 +206,19 @@ For information about authentication, see this `documentation`_.
 
 .. _documentation: https://cloud.google.com/docs/authentication/production
 
+You can modify the Access Control List (ACL) policy used for the stored files,
+which is defined by the :setting:`FILES_STORE_GCS_ACL` and
+:setting:`IMAGES_STORE_GCS_ACL` settings. By default, the ACL is set to
+``''`` (empty string) which means that Cloud Storage applies the bucket's default object ACL to the object.
+To make the files publicly available use the ``publicRead``
+policy::
+
+    IMAGES_STORE_GCS_ACL = 'publicRead'
+
+For more information, see `Predefined ACLs`_ in the Google Cloud Platform Developer Guide.
+
+.. _Predefined ACLs: https://cloud.google.com/storage/docs/access-control/lists#predefined-acl
+
 Usage example
 =============
 
diff --git a/scrapy/pipelines/files.py b/scrapy/pipelines/files.py
index ab18a727d..510cc23c7 100644
--- a/scrapy/pipelines/files.py
+++ b/scrapy/pipelines/files.py
@@ -208,6 +208,10 @@ class GCSFilesStore(object):
 
     CACHE_CONTROL = 'max-age=172800'
 
+    # The bucket's default object ACL will be applied to the object.
+    # Overriden from settings.FILES_STORE_GCS_ACL in FilesPipeline.from_settings.
+    POLICY = None
+
     def __init__(self, uri):
         from google.cloud import storage
         client = storage.Client(project=self.GCS_PROJECT_ID)
@@ -239,7 +243,8 @@ class GCSFilesStore(object):
         return threads.deferToThread(
             blob.upload_from_string,
             data=buf.getvalue(),
-            content_type=self._get_content_type(headers)
+            content_type=self._get_content_type(headers),
+            predefined_acl=self.POLICY
         )
 
 
@@ -314,6 +319,7 @@ class FilesPipeline(MediaPipeline):
 
         gcs_store = cls.STORE_SCHEMES['gs']
         gcs_store.GCS_PROJECT_ID = settings['GCS_PROJECT_ID']
+        gcs_store.POLICY = settings['FILES_STORE_GCS_ACL'] or None
 
         store_uri = settings['FILES_STORE']
         return cls(store_uri, settings=settings)
diff --git a/scrapy/pipelines/images.py b/scrapy/pipelines/images.py
index c5fc12afe..95323c613 100644
--- a/scrapy/pipelines/images.py
+++ b/scrapy/pipelines/images.py
@@ -93,6 +93,7 @@ class ImagesPipeline(FilesPipeline):
 
         gcs_store = cls.STORE_SCHEMES['gs']
         gcs_store.GCS_PROJECT_ID = settings['GCS_PROJECT_ID']
+        gcs_store.POLICY = settings['IMAGES_STORE_GCS_ACL'] or None
 
         store_uri = settings['IMAGES_STORE']
         return cls(store_uri, settings=settings)
diff --git a/scrapy/settings/default_settings.py b/scrapy/settings/default_settings.py
index ead511473..36e17ef6b 100644
--- a/scrapy/settings/default_settings.py
+++ b/scrapy/settings/default_settings.py
@@ -159,6 +159,7 @@ FEED_EXPORTERS_BASE = {
 FEED_EXPORT_INDENT = 0
 
 FILES_STORE_S3_ACL = 'private'
+FILES_STORE_GCS_ACL = ''
 
 FTP_USER = 'anonymous'
 FTP_PASSWORD = 'guest'
@@ -181,6 +182,7 @@ HTTPPROXY_ENABLED = True
 HTTPPROXY_AUTH_ENCODING = 'latin-1'
 
 IMAGES_STORE_S3_ACL = 'private'
+IMAGES_STORE_GCS_ACL = ''
 
 ITEM_PROCESSOR = 'scrapy.pipelines.ItemPipelineManager'
 
diff --git a/scrapy/utils/test.py b/scrapy/utils/test.py
index 60b931f48..4b935c51b 100644
--- a/scrapy/utils/test.py
+++ b/scrapy/utils/test.py
@@ -57,8 +57,9 @@ def get_gcs_content_and_delete(bucket, path):
     bucket = client.get_bucket(bucket)
     blob = bucket.get_blob(path)
     content = blob.download_as_string()
+    acl = list(blob.acl)  # loads acl before it will be deleted
     bucket.delete_blob(path)
-    return content, blob
+    return content, acl, blob
 
 def get_crawler(spidercls=None, settings_dict=None):
     """Return an unconfigured Crawler object. If settings_dict is given, it
diff --git a/tests/test_pipeline_files.py b/tests/test_pipeline_files.py
index c761bd606..728a74803 100644
--- a/tests/test_pipeline_files.py
+++ b/tests/test_pipeline_files.py
@@ -388,17 +388,20 @@ class TestGCSFilesStore(unittest.TestCase):
         meta = {'foo': 'bar'}
         path = 'full/filename'
         store = GCSFilesStore(uri)
+        store.POLICY = 'authenticatedRead'
+        expected_policy = {'role': 'READER', 'entity': 'allAuthenticatedUsers'}
         yield store.persist_file(path, buf, info=None, meta=meta, headers=None)
         s = yield store.stat_file(path, info=None)
         self.assertIn('last_modified', s)
         self.assertIn('checksum', s)
         self.assertEqual(s['checksum'], 'zc2oVgXkbQr2EQdSdw3OPA==')
         u = urlparse(uri)
-        content, blob = get_gcs_content_and_delete(u.hostname, u.path[1:]+path)
+        content, acl, blob = get_gcs_content_and_delete(u.hostname, u.path[1:]+path)
         self.assertEqual(content, data)
         self.assertEqual(blob.metadata, {'foo': 'bar'})
         self.assertEqual(blob.cache_control, GCSFilesStore.CACHE_CONTROL)
         self.assertEqual(blob.content_type, 'application/octet-stream')
+        self.assertIn(expected_policy, acl)
 
 
 class ItemWithFiles(Item):