diff --git a/apps/dav/appinfo/info.xml b/apps/dav/appinfo/info.xml
index 53825f5507208..3c4e266ddd363 100644
--- a/apps/dav/appinfo/info.xml
+++ b/apps/dav/appinfo/info.xml
@@ -5,7 +5,7 @@
 	<name>WebDAV</name>
 	<summary>WebDAV endpoint</summary>
 	<description>WebDAV endpoint</description>
-	<version>1.17.0</version>
+	<version>1.18.0</version>
 	<licence>agpl</licence>
 	<author>owncloud.org</author>
 	<namespace>DAV</namespace>
@@ -55,6 +55,7 @@
 
 	<settings>
 		<admin>OCA\DAV\Settings\CalDAVSettings</admin>
+		<admin>OCA\DAV\Settings\CardDAVSettings</admin>
 	</settings>
 
 	<activity>
diff --git a/apps/dav/appinfo/v1/carddav.php b/apps/dav/appinfo/v1/carddav.php
index dbab1ae9681a0..0b1486507e9d5 100644
--- a/apps/dav/appinfo/v1/carddav.php
+++ b/apps/dav/appinfo/v1/carddav.php
@@ -57,7 +57,7 @@
 	'principals/'
 );
 $db = \OC::$server->getDatabaseConnection();
-$cardDavBackend = new CardDavBackend($db, $principalBackend, \OC::$server->getUserManager(), \OC::$server->getGroupManager(), \OC::$server->get(\OCP\EventDispatcher\IEventDispatcher::class), \OC::$server->getEventDispatcher());
+$cardDavBackend = new CardDavBackend($db, $principalBackend, \OC::$server->getUserManager(), \OC::$server->getGroupManager(), \OC::$server->get(\OCP\EventDispatcher\IEventDispatcher::class), \OC::$server->getEventDispatcher(), \OC::$server->getConfig());
 
 $debugging = \OC::$server->getConfig()->getSystemValue('debug', false);
 
diff --git a/apps/dav/composer/composer/autoload_classmap.php b/apps/dav/composer/composer/autoload_classmap.php
index aaa5e82da0455..4f6a42764084b 100644
--- a/apps/dav/composer/composer/autoload_classmap.php
+++ b/apps/dav/composer/composer/autoload_classmap.php
@@ -239,6 +239,7 @@
     'OCA\\DAV\\Search\\TasksSearchProvider' => $baseDir . '/../lib/Search/TasksSearchProvider.php',
     'OCA\\DAV\\Server' => $baseDir . '/../lib/Server.php',
     'OCA\\DAV\\Settings\\CalDAVSettings' => $baseDir . '/../lib/Settings/CalDAVSettings.php',
+    'OCA\\DAV\\Settings\\CardDAVSettings' => $baseDir . '/../lib/Settings/CardDAVSettings.php',
     'OCA\\DAV\\Storage\\PublicOwnerWrapper' => $baseDir . '/../lib/Storage/PublicOwnerWrapper.php',
     'OCA\\DAV\\SystemTag\\SystemTagMappingNode' => $baseDir . '/../lib/SystemTag/SystemTagMappingNode.php',
     'OCA\\DAV\\SystemTag\\SystemTagNode' => $baseDir . '/../lib/SystemTag/SystemTagNode.php',
diff --git a/apps/dav/composer/composer/autoload_static.php b/apps/dav/composer/composer/autoload_static.php
index 0dc34f5a3172b..01f5a645dd9f7 100644
--- a/apps/dav/composer/composer/autoload_static.php
+++ b/apps/dav/composer/composer/autoload_static.php
@@ -254,6 +254,7 @@ class ComposerStaticInitDAV
         'OCA\\DAV\\Search\\TasksSearchProvider' => __DIR__ . '/..' . '/../lib/Search/TasksSearchProvider.php',
         'OCA\\DAV\\Server' => __DIR__ . '/..' . '/../lib/Server.php',
         'OCA\\DAV\\Settings\\CalDAVSettings' => __DIR__ . '/..' . '/../lib/Settings/CalDAVSettings.php',
+        'OCA\\DAV\\Settings\\CardDAVSettings' => __DIR__ . '/..' . '/../lib/Settings/CardDAVSettings.php',
         'OCA\\DAV\\Storage\\PublicOwnerWrapper' => __DIR__ . '/..' . '/../lib/Storage/PublicOwnerWrapper.php',
         'OCA\\DAV\\SystemTag\\SystemTagMappingNode' => __DIR__ . '/..' . '/../lib/SystemTag/SystemTagMappingNode.php',
         'OCA\\DAV\\SystemTag\\SystemTagNode' => __DIR__ . '/..' . '/../lib/SystemTag/SystemTagNode.php',
diff --git a/apps/dav/js/settings-admin-carddav.js b/apps/dav/js/settings-admin-carddav.js
new file mode 100644
index 0000000000000..daaecae8e5fc6
--- /dev/null
+++ b/apps/dav/js/settings-admin-carddav.js
@@ -0,0 +1,26 @@
+/**
+ * @copyright 2017, Bjoern Schiessle <bjoern@schiessle.org>
+ *
+ * @author Bjoern Schiessle <bjoern@schiessle.org>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+"use strict";
+
+document.getElementById('carddavExposeSystemAddressBook').addEventListener('change', function(e) {
+	OCP.AppConfig.setValue('dav', 'exposeSystemAddressBook', e.target.checked ? 'yes' : 'no');
+});
diff --git a/apps/dav/lib/CardDAV/CardDavBackend.php b/apps/dav/lib/CardDAV/CardDavBackend.php
index 14ade3f16e218..33bfe52224c3a 100644
--- a/apps/dav/lib/CardDAV/CardDavBackend.php
+++ b/apps/dav/lib/CardDAV/CardDavBackend.php
@@ -47,6 +47,7 @@
 use OCA\DAV\Events\CardUpdatedEvent;
 use OCP\DB\QueryBuilder\IQueryBuilder;
 use OCP\EventDispatcher\IEventDispatcher;
+use OCP\IConfig;
 use OCP\IDBConnection;
 use OCP\IGroupManager;
 use OCP\IUser;
@@ -96,6 +97,9 @@ class CardDavBackend implements BackendInterface, SyncSupport {
 	/** @var IEventDispatcher */
 	private $dispatcher;
 
+	/** @var IConfig */
+	private $config;
+
 	/** @var EventDispatcherInterface */
 	private $legacyDispatcher;
 
@@ -110,18 +114,21 @@ class CardDavBackend implements BackendInterface, SyncSupport {
 	 * @param IGroupManager $groupManager
 	 * @param IEventDispatcher $dispatcher
 	 * @param EventDispatcherInterface $legacyDispatcher
+	 * @param IConfig $config
 	 */
 	public function __construct(IDBConnection $db,
 								Principal $principalBackend,
 								IUserManager $userManager,
 								IGroupManager $groupManager,
 								IEventDispatcher $dispatcher,
-								EventDispatcherInterface $legacyDispatcher) {
+								EventDispatcherInterface $legacyDispatcher,
+								IConfig $config) {
 		$this->db = $db;
 		$this->principalBackend = $principalBackend;
 		$this->userManager = $userManager;
 		$this->dispatcher = $dispatcher;
 		$this->legacyDispatcher = $legacyDispatcher;
+		$this->config = $config;
 		$this->sharingBackend = new Backend($this->db, $this->userManager, $groupManager, $principalBackend, 'addressbook');
 	}
 
@@ -242,6 +249,34 @@ public function getAddressBooksForUser($principalUri) {
 		}
 		$result->closeCursor();
 
+		// query for system addressbooks
+		$includeSystemAddressBook = $this->config->getAppValue('dav', 'exposeSystemAddressBook', 'no') === 'yes';
+		if ($includeSystemAddressBook) {
+			$principalUri="principals/system/system";
+			$query = $this->db->getQueryBuilder();
+			$query->select(['id', 'uri', 'displayname', 'principaluri', 'description', 'synctoken'])
+				->from('addressbooks')
+				->where($query->expr()->eq('principaluri', $query->createNamedParameter($principalUri)));
+			$result = $query->execute();
+
+			while ($row = $result->fetch()) {
+				$addressBooks[$row['id']] = [
+					'id' => $row['id'],
+					'uri' => "system-address-book",
+					'principaluri' => $principalUriOriginal,
+					'{DAV:}displayname' => "System address book",
+					'{' . Plugin::NS_CARDDAV . '}addressbook-description' => $row['description'],
+					'{http://calendarserver.org/ns/}getctag' => $row['synctoken'],
+					'{http://sabredav.org/ns}sync-token' => $row['synctoken'] ?: '0',
+					'{' . \OCA\DAV\DAV\Sharing\Plugin::NS_OWNCLOUD . '}owner-principal' => $row['principaluri'],
+					$readOnlyPropertyName => true,
+				];
+
+				$this->addOwnerPrincipal($addressBooks[$row['id']]);
+			}
+			$result->closeCursor();
+		}
+
 		return array_values($addressBooks);
 	}
 
diff --git a/apps/dav/lib/RootCollection.php b/apps/dav/lib/RootCollection.php
index 83f3691959ba7..ce5744e609303 100644
--- a/apps/dav/lib/RootCollection.php
+++ b/apps/dav/lib/RootCollection.php
@@ -128,11 +128,11 @@ public function __construct() {
 		);
 
 		$pluginManager = new PluginManager(\OC::$server, \OC::$server->query(IAppManager::class));
-		$usersCardDavBackend = new CardDavBackend($db, $userPrincipalBackend, $userManager, $groupManager, $dispatcher, $legacyDispatcher);
+		$usersCardDavBackend = new CardDavBackend($db, $userPrincipalBackend, $userManager, $groupManager, $dispatcher, $legacyDispatcher, \OC::$server->getConfig());
 		$usersAddressBookRoot = new AddressBookRoot($userPrincipalBackend, $usersCardDavBackend, $pluginManager, 'principals/users');
 		$usersAddressBookRoot->disableListing = $disableListing;
 
-		$systemCardDavBackend = new CardDavBackend($db, $userPrincipalBackend, $userManager, $groupManager, $dispatcher, $legacyDispatcher);
+		$systemCardDavBackend = new CardDavBackend($db, $userPrincipalBackend, $userManager, $groupManager, $dispatcher, $legacyDispatcher,  \OC::$server->getConfig());
 		$systemAddressBookRoot = new AddressBookRoot(new SystemPrincipalBackend(), $systemCardDavBackend, $pluginManager, 'principals/system');
 		$systemAddressBookRoot->disableListing = $disableListing;
 
diff --git a/apps/dav/lib/Settings/CardDAVSettings.php b/apps/dav/lib/Settings/CardDAVSettings.php
new file mode 100644
index 0000000000000..53435905bf481
--- /dev/null
+++ b/apps/dav/lib/Settings/CardDAVSettings.php
@@ -0,0 +1,68 @@
+<?php
+/**
+ * @copyright 2020, Bjoern Schiessle <bjoern@schiessle.org>
+ *
+ * @author Bjoern Schiessle <bjoern@schiessle.org>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace OCA\DAV\Settings;
+
+use OCP\AppFramework\Http\TemplateResponse;
+use OCP\IConfig;
+use OCP\Settings\ISettings;
+
+class CardDAVSettings implements ISettings {
+
+	/** @var IConfig */
+	private $config;
+
+	/**
+	 * CalDAVSettings constructor.
+	 *
+	 * @param IConfig $config
+	 */
+	public function __construct(IConfig $config) {
+		$this->config = $config;
+	}
+
+	/**
+	 * @return TemplateResponse
+	 */
+	public function getForm() {
+		$parameters = [
+			'expose_system_address_book' => $this->config->getAppValue('dav', 'exposeSystemAddressBook', 'no'),
+		];
+
+		return new TemplateResponse('dav', 'settings-admin-carddav', $parameters);
+	}
+
+	/**
+	 * @return string
+	 */
+	public function getSection() {
+		return 'groupware';
+	}
+
+	/**
+	 * @return int
+	 */
+	public function getPriority() {
+		return 10;
+	}
+}
diff --git a/apps/dav/templates/settings-admin-carddav.php b/apps/dav/templates/settings-admin-carddav.php
new file mode 100644
index 0000000000000..b82a9168f69c3
--- /dev/null
+++ b/apps/dav/templates/settings-admin-carddav.php
@@ -0,0 +1,42 @@
+<?php
+/**
+ * @copyright 2020, Bjoern Schiessle <bjoern@schiessle.org>
+ *
+ * @author Bjoern Schiessle <bjoern@schiessle.org>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+script('dav', [
+	'settings-admin-carddav'
+]);
+
+/** @var \OCP\IL10N $l */
+/** @var array $_ */
+?>
+<form id="CardDAV" class="section">
+	<h2><?php p($l->t('Addressbook server')); ?></h2>
+	<p>
+		<input type="checkbox" name="carddav_expose_system-address-book" id="carddavExposeSystemAddressBook" class="checkbox"
+			<?php ($_['expose_system_address_book'] === 'yes') ? print_unescaped('checked="checked"') : null ?>/>
+		<label for="carddavExposeSystemAddressBook"><?php p($l->t('Expose system address book')); ?></label>
+		<br>
+		<em>
+			<?php print_unescaped($l->t('Only information set to "Public" or "Trusted" in the user\'s personal settings will be exposed.')); ?>
+		</em>
+	</p>
+</form>
diff --git a/apps/dav/tests/unit/CardDAV/CardDavBackendTest.php b/apps/dav/tests/unit/CardDAV/CardDavBackendTest.php
index 95617001b3188..80012006f71b8 100644
--- a/apps/dav/tests/unit/CardDAV/CardDavBackendTest.php
+++ b/apps/dav/tests/unit/CardDAV/CardDavBackendTest.php
@@ -82,6 +82,9 @@ class CardDavBackendTest extends TestCase {
 	/** @var IEventDispatcher|\PHPUnit\Framework\MockObject\MockObject */
 	private $dispatcher;
 
+	/** @var IConfig|\PHPUnit\Framework\MockObject\MockObject */
+	private $config;
+
 	/** @var  IDBConnection */
 	private $db;
 
@@ -129,6 +132,9 @@ class CardDavBackendTest extends TestCase {
 	protected function setUp(): void {
 		parent::setUp();
 
+		$this->config = $this->createMock(IConfig::class);
+		$this->config->expects($this->any())->method('getAppValue')
+			->with('dav', 'exposeSystemAddressBook', 'no')->willReturn('no');
 		$this->userManager = $this->createMock(IUserManager::class);
 		$this->groupManager = $this->createMock(IGroupManager::class);
 		$this->principal = $this->getMockBuilder(Principal::class)
@@ -156,7 +162,7 @@ protected function setUp(): void {
 
 		$this->db = \OC::$server->getDatabaseConnection();
 
-		$this->backend = new CardDavBackend($this->db, $this->principal, $this->userManager, $this->groupManager, $this->dispatcher, $this->legacyDispatcher);
+		$this->backend = new CardDavBackend($this->db, $this->principal, $this->userManager, $this->groupManager, $this->dispatcher, $this->legacyDispatcher, $this->config);
 		// start every test with a empty cards_properties and cards table
 		$query = $this->db->getQueryBuilder();
 		$query->delete('cards_properties')->execute();
@@ -246,7 +252,7 @@ public function testCardOperations() {
 
 		/** @var CardDavBackend | \PHPUnit\Framework\MockObject\MockObject $backend */
 		$backend = $this->getMockBuilder(CardDavBackend::class)
-				->setConstructorArgs([$this->db, $this->principal, $this->userManager, $this->groupManager, $this->dispatcher, $this->legacyDispatcher])
+				->setConstructorArgs([$this->db, $this->principal, $this->userManager, $this->groupManager, $this->dispatcher, $this->legacyDispatcher, $this->config])
 				->setMethods(['updateProperties', 'purgeProperties'])->getMock();
 
 		// create a new address book
@@ -318,7 +324,7 @@ public function testCardOperations() {
 
 	public function testMultiCard() {
 		$this->backend = $this->getMockBuilder(CardDavBackend::class)
-			->setConstructorArgs([$this->db, $this->principal, $this->userManager, $this->groupManager, $this->dispatcher, $this->legacyDispatcher])
+			->setConstructorArgs([$this->db, $this->principal, $this->userManager, $this->groupManager, $this->dispatcher, $this->legacyDispatcher, $this->config])
 			->setMethods(['updateProperties'])->getMock();
 
 		// create a new address book
@@ -371,7 +377,7 @@ public function testMultiCard() {
 
 	public function testMultipleUIDOnDifferentAddressbooks() {
 		$this->backend = $this->getMockBuilder(CardDavBackend::class)
-			->setConstructorArgs([$this->db, $this->principal, $this->userManager, $this->groupManager, $this->dispatcher, $this->legacyDispatcher])
+			->setConstructorArgs([$this->db, $this->principal, $this->userManager, $this->groupManager, $this->dispatcher, $this->legacyDispatcher, $this->config])
 			->setMethods(['updateProperties'])->getMock();
 
 		// create 2 new address books
@@ -393,7 +399,7 @@ public function testMultipleUIDOnDifferentAddressbooks() {
 
 	public function testMultipleUIDDenied() {
 		$this->backend = $this->getMockBuilder(CardDavBackend::class)
-			->setConstructorArgs([$this->db, $this->principal, $this->userManager, $this->groupManager, $this->dispatcher, $this->legacyDispatcher])
+			->setConstructorArgs([$this->db, $this->principal, $this->userManager, $this->groupManager, $this->dispatcher, $this->legacyDispatcher, $this->config])
 			->setMethods(['updateProperties'])->getMock();
 
 		// create a new address book
@@ -414,7 +420,7 @@ public function testMultipleUIDDenied() {
 
 	public function testNoValidUID() {
 		$this->backend = $this->getMockBuilder(CardDavBackend::class)
-			->setConstructorArgs([$this->db, $this->principal, $this->userManager, $this->groupManager, $this->dispatcher, $this->legacyDispatcher])
+			->setConstructorArgs([$this->db, $this->principal, $this->userManager, $this->groupManager, $this->dispatcher, $this->legacyDispatcher, $this->config])
 			->setMethods(['updateProperties'])->getMock();
 
 		// create a new address book
@@ -431,7 +437,7 @@ public function testNoValidUID() {
 
 	public function testDeleteWithoutCard() {
 		$this->backend = $this->getMockBuilder(CardDavBackend::class)
-			->setConstructorArgs([$this->db, $this->principal, $this->userManager, $this->groupManager, $this->dispatcher, $this->legacyDispatcher])
+			->setConstructorArgs([$this->db, $this->principal, $this->userManager, $this->groupManager, $this->dispatcher, $this->legacyDispatcher, $this->config])
 			->setMethods([
 				'getCardId',
 				'addChange',
@@ -471,7 +477,7 @@ public function testDeleteWithoutCard() {
 
 	public function testSyncSupport() {
 		$this->backend = $this->getMockBuilder(CardDavBackend::class)
-			->setConstructorArgs([$this->db, $this->principal, $this->userManager, $this->groupManager, $this->dispatcher, $this->legacyDispatcher])
+			->setConstructorArgs([$this->db, $this->principal, $this->userManager, $this->groupManager, $this->dispatcher, $this->legacyDispatcher, $this->config])
 			->setMethods(['updateProperties'])->getMock();
 
 		// create a new address book
@@ -537,7 +543,7 @@ public function testUpdateProperties() {
 		$cardId = 2;
 
 		$backend = $this->getMockBuilder(CardDavBackend::class)
-			->setConstructorArgs([$this->db, $this->principal, $this->userManager, $this->groupManager, $this->dispatcher, $this->legacyDispatcher])
+			->setConstructorArgs([$this->db, $this->principal, $this->userManager, $this->groupManager, $this->dispatcher, $this->legacyDispatcher, $this->config])
 			->setMethods(['getCardId'])->getMock();
 
 		$backend->expects($this->any())->method('getCardId')->willReturn($cardId);