diff --git a/apps/files_external/js/settings.js b/apps/files_external/js/settings.js
index ffe1e972071..983348397d1 100644
--- a/apps/files_external/js/settings.js
+++ b/apps/files_external/js/settings.js
@@ -48,6 +48,12 @@ var MOUNT_OPTIONS_DROPDOWN_TEMPLATE =
 	'				<label for="mountOptionsEncoding">{{mountOptionsEncodingLabel}}</label>'+
 	'			</span>'+
 	'		</li>'+
+	'		<li class="optionRow">' +
+	'			<span class="menuitem">' +
+	'				<input id="mountOptionsReadOnly" class="checkbox" name="readonly" type="checkbox" value="true"/>' +
+	'				<label for="mountOptionsReadOnly">{{t "files_external" "Read only"}}</label>' +
+	'			</span>' +
+	'		</li>' +
 	'	</ul>'+
 	'</div>';
 
@@ -916,7 +922,8 @@ MountConfigListView.prototype = _.extend({
 				'previews': true,
 				'enable_sharing': false,
 				'filesystem_check_changes': 1,
-				'encoding_compatibility': false
+				'encoding_compatibility': false,
+				'readonly': false,
 			}));
 		}
 
@@ -1303,7 +1310,8 @@ MountConfigListView.prototype = _.extend({
 			'previews',
 			'filesystem_check_changes',
 			'enable_sharing',
-			'encoding_compatibility'
+			'encoding_compatibility',
+			'readonly'
 		];
 		if (this._encryptionEnabled) {
 			visibleOptions.push('encrypt');
diff --git a/apps/files_external/lib/Command/ListCommand.php b/apps/files_external/lib/Command/ListCommand.php
index efb2669e281..89bdcf5e5d6 100644
--- a/apps/files_external/lib/Command/ListCommand.php
+++ b/apps/files_external/lib/Command/ListCommand.php
@@ -192,7 +192,8 @@ class ListCommand extends Base {
 				'previews' => true,
 				'filesystem_check_changes' => 1,
 				'enable_sharing' => false,
-				'encoding_compatibility' => false
+				'encoding_compatibility' => false,
+				'readonly' => false,
 			];
 			$rows = array_map(function (StorageConfig $config) use ($userId, $defaultMountOptions, $full) {
 				$storageConfig = $config->getBackendOptions();
diff --git a/apps/files_external/templates/settings.php b/apps/files_external/templates/settings.php
index 895be719ab4..236faf37d6d 100644
--- a/apps/files_external/templates/settings.php
+++ b/apps/files_external/templates/settings.php
@@ -12,6 +12,7 @@
 	$l->t("Check for changes");
 	$l->t("Never");
 	$l->t("Once every direct access");
+	$l->t('Read only');
 
 	script('files_external', 'settings');
 	style('files_external', 'settings');
diff --git a/lib/private/legacy/util.php b/lib/private/legacy/util.php
index d3599d14e7a..356d336f687 100644
--- a/lib/private/legacy/util.php
+++ b/lib/private/legacy/util.php
@@ -259,6 +259,23 @@ class OC_Util {
 			return $storage;
 		});
 
+		\OC\Files\Filesystem::addStorageWrapper('readonly', function ($mountPoint, \OCP\Files\Storage\IStorage $storage, \OCP\Files\Mount\IMountPoint $mount) {
+			/*
+			 * Do not allow any operations that modify the storage
+			 */
+			if ($mount->getOption('readonly', false)) {
+				return new \OC\Files\Storage\Wrapper\PermissionsMask([
+					'storage' => $storage,
+					'mask' => \OCP\Constants::PERMISSION_ALL & ~(
+						\OCP\Constants::PERMISSION_UPDATE |
+						\OCP\Constants::PERMISSION_CREATE |
+						\OCP\Constants::PERMISSION_DELETE
+					),
+				]);
+			}
+			return $storage;
+		});
+
 		OC_Hook::emit('OC_Filesystem', 'preSetup', array('user' => $user));
 		\OC\Files\Filesystem::logWarningWhenAddingStorageWrapper(true);