diff --git a/src/Config/ActivityPubModule.php b/src/Config/ActivityPubModule.php
index 331307f..99914a8 100644
--- a/src/Config/ActivityPubModule.php
+++ b/src/Config/ActivityPubModule.php
@@ -20,6 +20,7 @@ use ActivityPub\Controllers\PostController;
 use ActivityPub\Crypto\HttpSignatureService;
 use ActivityPub\Database\PrefixNamingStrategy;
 use ActivityPub\Http\Router;
+use ActivityPub\Objects\BlockService;
 use ActivityPub\Objects\CollectionsService;
 use ActivityPub\Objects\ContextProvider;
 use ActivityPub\Objects\IdProvider;
@@ -108,10 +109,14 @@ class ActivityPubModule
             ->addArgument( new Reference( RandomProvider::class ) )
             ->addArgument( $config->getIdPathPrefix() );
 
+        $this->injector->register( BlockService::class, BlockService::class )
+            ->addArgument( new Reference( ObjectsService::class ) );
+
         $this->injector->register( GetController::class, GetController::class )
             ->addArgument( new Reference( ObjectsService::class ) )
             ->addArgument( new Reference( CollectionsService::class ) )
-            ->addArgument( new Reference( AuthService::class ) );
+            ->addArgument( new Reference( AuthService::class ) )
+            ->addArgument( new Reference( BlockService::class ) );
 
         $this->injector->register( PostController::class, PostController::class )
             ->addArgument( new Reference( EventDispatcher::class ) )
diff --git a/src/Controllers/GetController.php b/src/Controllers/GetController.php
index 5a9b656..bc32220 100644
--- a/src/Controllers/GetController.php
+++ b/src/Controllers/GetController.php
@@ -3,6 +3,8 @@
 namespace ActivityPub\Controllers;
 
 use ActivityPub\Auth\AuthService;
+use ActivityPub\Entities\ActivityPubObject;
+use ActivityPub\Objects\BlockService;
 use ActivityPub\Objects\CollectionsService;
 use ActivityPub\Objects\ObjectsService;
 use Symfony\Component\HttpFoundation\JsonResponse;
@@ -32,13 +34,20 @@ class GetController
      */
     private $authService;
 
+    /**
+     * @var BlockService
+     */
+    private $blockService;
+
     public function __construct( ObjectsService $objectsService,
                                  CollectionsService $collectionsService,
-                                 AuthService $authService )
+                                 AuthService $authService,
+                                 BlockService $blockService )
     {
         $this->objectsService = $objectsService;
         $this->collectionsService = $collectionsService;
         $this->authService = $authService;
+        $this->blockService = $blockService;
     }
 
     /**
@@ -66,7 +75,37 @@ class GetController
         if ( $object->hasField( 'type' ) &&
             ( $object['type'] === 'Collection' ||
                 $object['type'] === 'OrderedCollection' ) ) {
-            $pagedCollection = $this->collectionsService->pageAndFilterCollection( $request, $object );
+            if ( $object->hasReferencingField( 'inbox' ) ) {
+                // TODO figure out what to pass in here
+                $blockedActorIds = $this->blockService->getBlockedActorIds();
+                $filterFunc = function ( ActivityPubObject $item ) use ( $request, $blockedActorIds ) {
+                    $authorized = $this->authService->isAuthorized( $request, $item );
+                    foreach ( array( 'actor', 'attributedTo' ) as $actorField ) {
+                        if ( $item->hasField( $actorField ) ) {
+                            $actorFieldValue = $item->getFieldValue( $actorField );
+                            if ( ! $actorFieldValue ) {
+                                continue;
+                            }
+                            if ( is_string( $actorFieldValue &&
+                                in_array( $actorFieldValue, $blockedActorIds ) ) ) {
+                                $authorized = false;
+                                break;
+                            } else if ( $actorFieldValue instanceof ActivityPubObject &&
+                            in_array( $actorFieldValue['id'], $blockedActorIds ) ) {
+                                $authorized = false;
+                                break;
+                            }
+                        }
+                    }
+                    return $authorized;
+                }
+            } else {
+                $filterFunc = function ( ActivityPubObject $item ) use ( $request ) {
+                    return $this->authService->isAuthorized( $request, $item );
+                };
+            }
+            $pagedCollection = $this->collectionsService->pageAndFilterCollection( $request, $object, $filterFunc );
+
             return new JsonResponse( $pagedCollection );
         }
         $response = new JsonResponse( $object->asArray() );
diff --git a/src/Objects/BlockService.php b/src/Objects/BlockService.php
new file mode 100644
index 0000000..dcd791d
--- /dev/null
+++ b/src/Objects/BlockService.php
@@ -0,0 +1,21 @@
+<?php
+
+namespace ActivityPub\Objects;
+
+class BlockService
+{
+    /**
+     * @var ObjectsService
+     */
+    private $objectsService;
+
+    public function __construct( ObjectsService $objectsService )
+    {
+        $this->objectsService = $objectsService;
+    }
+
+    public function getBlockedActorIds()
+    {
+        // TODO implement me
+    }
+}
\ No newline at end of file
diff --git a/src/Objects/CollectionsService.php b/src/Objects/CollectionsService.php
index 285ff3d..db7bd2b 100644
--- a/src/Objects/CollectionsService.php
+++ b/src/Objects/CollectionsService.php
@@ -8,6 +8,7 @@ use ActivityPub\Auth\AuthService;
 use ActivityPub\Entities\ActivityPubObject;
 use ActivityPub\Entities\Field;
 use ActivityPub\Utils\DateTimeProvider;
+use Closure;
 use Doctrine\ORM\EntityManager;
 use Exception;
 use GuzzleHttp\Client;
@@ -77,14 +78,18 @@ class CollectionsService
      * Returns the collection paged and filtered by the request's authorization status
      * @param Request $request
      * @param ActivityPubObject $collection
+     * @param Closure $filterFunc The function to filter by. Should be a closure that
+     *                            takes an ActivityPubObject and returns a boolean, where
+     *                            true means keep the item and false means filter it out
      * @return array
      */
     public function pageAndFilterCollection( Request $request,
-                                             ActivityPubObject $collection )
+                                             ActivityPubObject $collection,
+                                             Closure $filterFunc )
     {
         if ( $request->query->has( 'offset' ) ) {
             return $this->getCollectionPage(
-                $collection, $request, intval( $request->query->get( 'offset' ) ), $this->pageSize
+                $collection, $request, intval( $request->query->get( 'offset' ) ), $this->pageSize, $filterFunc
             );
         }
         $colArr = array();
@@ -98,7 +103,7 @@ class CollectionsService
             }
         }
         $firstPage = $this->getCollectionPage(
-            $collection, $request, 0, $this->pageSize
+            $collection, $request, 0, $this->pageSize, $filterFunc
         );
         $colArr['first'] = $firstPage;
         return $colArr;
@@ -107,7 +112,8 @@ class CollectionsService
     private function getCollectionPage( ActivityPubObject $collection,
                                         Request $request,
                                         $offset,
-                                        $pageSize )
+                                        $pageSize,
+                                        Closure $filterFunc )
     {
         $itemsKey = 'items';
         $pageType = 'CollectionPage';
@@ -133,7 +139,7 @@ class CollectionsService
             if ( is_string( $item ) ) {
                 $pageItems[] = $item;
                 $count++;
-            } else if ( $this->authService->isAuthorized( $request, $item ) ) {
+            } else if ( call_user_func( $filterFunc, $item ) ) {
                 $pageItems[] = $item->asArray( 1 );
                 $count++;
             }
diff --git a/test/Objects/BlockServiceTest.php b/test/Objects/BlockServiceTest.php
new file mode 100644
index 0000000..2e3dd74
--- /dev/null
+++ b/test/Objects/BlockServiceTest.php
@@ -0,0 +1,14 @@
+<?php
+
+namespace ActivityPub\Test\Objects;
+
+use ActivityPub\Test\TestConfig\APTestCase;
+
+class BlockServiceTest extends APTestCase
+{
+    public function testGetBlockedActorIds()
+    {
+        // TODO implement me
+        $this->assertTrue( false );
+    }
+}
\ No newline at end of file