diff --git a/framework/core/src/Extend/ServiceProvider.php b/framework/core/src/Extend/ServiceProvider.php
new file mode 100644
index 000000000..b2767cdcb
--- /dev/null
+++ b/framework/core/src/Extend/ServiceProvider.php
@@ -0,0 +1,40 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * For detailed copyright and license information, please view the
+ * LICENSE file that was distributed with this source code.
+ */
+
+namespace Flarum\Extend;
+
+use Flarum\Extension\Extension;
+use Illuminate\Contracts\Container\Container;
+
+class ServiceProvider implements ExtenderInterface
+{
+    private $providers = [];
+
+    /**
+     * Register a service provider.
+     *
+     * @param string $serviceProviderClass The ::class attribute of the service provider class.
+     * @return self
+     */
+    public function register(string $serviceProviderClass)
+    {
+        $this->providers[] = $serviceProviderClass;
+
+        return $this;
+    }
+
+    public function extend(Container $container, Extension $extension = null)
+    {
+        $app = $container->make('flarum');
+
+        foreach ($this->providers as $provider) {
+            $app->register($provider);
+        }
+    }
+}
diff --git a/framework/core/tests/integration/extenders/ServiceProviderTest.php b/framework/core/tests/integration/extenders/ServiceProviderTest.php
new file mode 100644
index 000000000..72f3af0b6
--- /dev/null
+++ b/framework/core/tests/integration/extenders/ServiceProviderTest.php
@@ -0,0 +1,119 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * For detailed copyright and license information, please view the
+ * LICENSE file that was distributed with this source code.
+ */
+
+namespace Flarum\Tests\integration\extenders;
+
+use Flarum\Extend;
+use Flarum\Foundation\AbstractServiceProvider;
+use Flarum\Tests\integration\TestCase;
+
+class ServiceProviderTest extends TestCase
+{
+    /**
+     * @test
+     */
+    public function providers_dont_work_by_default()
+    {
+        $this->app();
+
+        $this->assertIsArray(
+            $this->app->getContainer()->make('flarum.forum.middleware')
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function providers_first_register_order_is_correct()
+    {
+        $this->extend(
+            (new Extend\ServiceProvider())
+                ->register(CustomServiceProvider::class)
+        );
+
+        $this->app();
+
+        $this->assertEquals(
+            'overriden_by_custom_provider_register',
+            $this->app->getContainer()->make('flarum.forum.middleware')
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function providers_second_register_order_is_correct()
+    {
+        $this->extend(
+            (new Extend\ServiceProvider())
+                ->register(CustomServiceProvider::class)
+                ->register(SecondCustomServiceProvider::class)
+        );
+
+        $this->app();
+
+        $this->assertEquals(
+            'overriden_by_second_custom_provider_register',
+            $this->app->getContainer()->make('flarum.forum.middleware')
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function providers_boot_order_is_correct()
+    {
+        $this->extend(
+            (new Extend\ServiceProvider())
+                ->register(ThirdCustomProvider::class)
+                ->register(CustomServiceProvider::class)
+                ->register(SecondCustomServiceProvider::class)
+        );
+
+        $this->app();
+
+        $this->assertEquals(
+            'overriden_by_third_custom_provider_boot',
+            $this->app->getContainer()->make('flarum.forum.middleware')
+        );
+    }
+}
+
+class CustomServiceProvider extends AbstractServiceProvider
+{
+    public function register()
+    {
+        // First we override the singleton here.
+        $this->app->extend('flarum.forum.middleware', function () {
+            return 'overriden_by_custom_provider_register';
+        });
+    }
+}
+
+class SecondCustomServiceProvider extends AbstractServiceProvider
+{
+    public function register()
+    {
+        // Second we check that the singleton was overriden here.
+        $this->app->extend('flarum.forum.middleware', function ($forumRoutes) {
+            return 'overriden_by_second_custom_provider_register';
+        });
+    }
+}
+
+class ThirdCustomProvider extends AbstractServiceProvider
+{
+    public function boot()
+    {
+        // Third we override one last time here, to make sure this is the final result.
+        $this->app->extend('flarum.forum.middleware', function ($forumRoutes) {
+            return 'overriden_by_third_custom_provider_boot';
+        });
+    }
+}