diff --git a/code/extensions/ContentReviewDefaultSettings.php b/code/extensions/ContentReviewDefaultSettings.php
index 969b229..29b418c 100644
--- a/code/extensions/ContentReviewDefaultSettings.php
+++ b/code/extensions/ContentReviewDefaultSettings.php
@@ -51,6 +51,15 @@ class ContentReviewDefaultSettings extends DataExtension
      */
     private static $content_review_template = 'ContentReviewEmail';
 
+    /**
+     * The number of members in which the dropdown will morph into a gridfield
+     *
+     * @config
+     *
+     * @var int
+     */
+    private static $content_review_gridfield_threshold = 500;
+
     /**
      * @return string
      */
@@ -120,11 +129,19 @@ class ContentReviewDefaultSettings extends DataExtension
         $usersMap = $users->map('ID', 'Title')->toArray();
         asort($usersMap);
 
-        $userField = ListboxField::create('OwnerUsers', _t('ContentReview.PAGEOWNERUSERS', 'Users'), $usersMap)
-            ->setMultiple(true)
-            ->setAttribute('data-placeholder', _t('ContentReview.ADDUSERS', 'Add users'))
-            ->setDescription(_t('ContentReview.OWNERUSERSDESCRIPTION', 'Page owners that are responsible for reviews'));
-
+        if(Member::get()->count() > Config::inst()->get('SiteConfig', 'content_review_gridfield_threshold')) {
+            $gridfieldconfig = GridFieldConfig_RelationEditor::create();
+            $gridfieldconfig->removeComponentsByType(new GridFieldAddNewButton());
+            $userField = GridField::create('OwnerUsers', _t("ContentReview.PAGEOWNERUSERS", "Users"),
+                    $this->OwnerUsers(), $gridfieldconfig)
+                    ->setDescription(_t('ContentReview.OWNERUSERSDESCRIPTION', 'Page owners that are responsible for reviews'));
+        } else {
+            $userField = ListboxField::create('OwnerUsers', _t('ContentReview.PAGEOWNERUSERS', 'Users'), $usersMap)
+                ->setMultiple(true)
+                ->setAttribute('data-placeholder', _t('ContentReview.ADDUSERS', 'Add users'))
+                            ->setDescription(_t('ContentReview.OWNERUSERSDESCRIPTION', 'Page owners that are responsible for reviews'));
+        }
+		
         $fields->addFieldToTab('Root.ContentReview', $userField);
 
         $groupsMap = array();
diff --git a/code/extensions/SiteTreeContentReview.php b/code/extensions/SiteTreeContentReview.php
index 2ec8c38..8364f9e 100644
--- a/code/extensions/SiteTreeContentReview.php
+++ b/code/extensions/SiteTreeContentReview.php
@@ -344,18 +344,26 @@ class SiteTreeContentReview extends DataExtension implements PermissionProvider
 
         $viewersOptionsField = OptionsetField::create("ContentReviewType", _t("ContentReview.OPTIONS", "Options"), $options);
 
-        $users = Permission::get_members_by_permission(array("CMS_ACCESS_CMSMain", "ADMIN"));
-
+		$users = Permission::get_members_by_permission(array("CMS_ACCESS_CMSMain", "ADMIN"));
         $usersMap = $users->map("ID", "Title")->toArray();
-
         asort($usersMap);
 
-        $userField = ListboxField::create("OwnerUsers", _t("ContentReview.PAGEOWNERUSERS", "Users"), $usersMap)
-            ->setMultiple(true)
-            ->addExtraClass('custom-setting')
-            ->setAttribute("data-placeholder", _t("ContentReview.ADDUSERS", "Add users"))
-            ->setDescription(_t('ContentReview.OWNERUSERSDESCRIPTION', 'Page owners that are responsible for reviews'));
-
+        if(Member::get()->count() > Config::inst()->get('SiteConfig', 'content_review_gridfield_threshold')) {
+            // grid field for large numbers of users
+            $gridfieldconfig = GridFieldConfig_RelationEditor::create();
+            $gridfieldconfig->removeComponentsByType(new GridFieldAddNewButton());
+            $userField = GridField::create('OwnerUsers', _t("ContentReview.PAGEOWNERUSERS", "Users"),
+                    $this->OwnerUsers(), $gridfieldconfig)
+                ->setDescription(_t('ContentReview.OWNERUSERSDESCRIPTION', 'Page owners that are responsible for reviews'));
+        } else {
+            $userField = ListboxField::create("OwnerUsers", _t("ContentReview.PAGEOWNERUSERS", "Users"), $usersMap)
+                ->setMultiple(true)
+                ->addExtraClass('custom-setting')
+                ->setAttribute("data-placeholder", _t("ContentReview.ADDUSERS", "Add users"))
+                ->setDescription(_t('ContentReview.OWNERUSERSDESCRIPTION', 'Page owners that are responsible for reviews'));
+        }
+		
+		
         $groupsMap = array();
 
         foreach (Group::get() as $group) {
diff --git a/docs/en/userguide/index.md b/docs/en/userguide/index.md
index c2e58b4..a4c5389 100644
--- a/docs/en/userguide/index.md
+++ b/docs/en/userguide/index.md
@@ -22,4 +22,15 @@ To set a content review schedule for a page go to `Settings > Content Review`.
 CMS users without the permission to change the content review schedule can still see the settings
 and previous reviews in the same view, but cannot change anything.
 
-![](_images/content-review-settings-ro.png)
\ No newline at end of file
+![](_images/content-review-settings-ro.png)
+
+## If your database contains a large number of members
+
+The page owners selector will change from a ListboxField to a Gridfield in order 
+to prevent your browser from crashing. By default this numbers is 500. You can
+customise this threshold by editing your .yml with the following settings:
+
+```
+SiteTree:
+  content_review_gridfield_threshold: 500
+```
\ No newline at end of file
diff --git a/tests/SiteTreeContentReviewTest.php b/tests/SiteTreeContentReviewTest.php
index fbdb9d6..b1f07a0 100644
--- a/tests/SiteTreeContentReviewTest.php
+++ b/tests/SiteTreeContentReviewTest.php
@@ -334,4 +334,34 @@ class SiteTreeContentReviewTest extends ContentReviewBaseTest
 
         SS_Datetime::clear_mock_now();
     }
+    public function testSiteSettingsFieldsListBox()
+    {
+        $author = $this->objFromFixture("Member", "editor");
+
+        $this->logInAs($author);
+		
+        /** @var Page|SiteTreeContentReview $page */
+        $page = $this->objFromFixture("Page", "contact");
+
+        $fields = $page->getSettingsFields();
+		
+        $this->assertInstanceOf('ListboxField', $fields->dataFieldByName('OwnerUsers'));
+    }
+	
+    public function testSiteSettingsFieldsGridfield()
+    {
+        $author = $this->objFromFixture("Member", "editor");
+
+        $this->logInAs($author);
+
+        /** @var Page|SiteTreeContentReview $page */
+        $page = $this->objFromFixture("Page", "contact");
+
+        // update the minimum threshhold to change to gridfield
+        Config::inst()->update('SiteConfig', 'content_review_gridfield_threshold', 1);
+
+        $fields = $page->getSettingsFields();
+
+        $this->assertInstanceOf('GridField', $fields->dataFieldByName('OwnerUsers'));
+	}
 }