diff --git a/tests/integration/tests/test-networkoperations.php b/tests/integration/tests/test-networkoperations.php
index f61bd36..de8af1b 100644
--- a/tests/integration/tests/test-networkoperations.php
+++ b/tests/integration/tests/test-networkoperations.php
@@ -89,4 +89,37 @@ public function test_update_network_clears_cache() {
 		$this->assertEquals( 'newdomain.com', $updated_network->domain, 'Network should have updated domain without manual cache flush' );
 		$this->assertEquals( '/newpath/', $updated_network->path, 'Network should have updated path without manual cache flush' );
 	}
+
+	public function test_plugin_auto_activates_on_new_network() {
+		// Create a test user and grant super admin privileges.
+		$user_id = $this->factory->user->create(
+			array(
+				'role' => 'administrator',
+			)
+		);
+		grant_super_admin( $user_id );
+
+		// Create a test network using add_network().
+		$network_id = add_network(
+			array(
+				'domain'           => 'auto-activate-test.com',
+				'path'             => '/',
+				'site_name'        => 'Auto Activate Test',
+				'network_name'     => 'Test Network',
+				'user_id'          => $user_id,
+				'network_admin_id' => $user_id,
+			)
+		);
+
+		// Verify network was created successfully.
+		$this->assertNotWPError( $network_id, 'Network should be created successfully' );
+		$this->assertIsInt( $network_id, 'Network ID should be an integer' );
+
+		// Get the active sitewide plugins for the new network.
+		$active_plugins = get_network_option( $network_id, 'active_sitewide_plugins', array() );
+
+		// Verify the plugin is auto-activated.
+		$this->assertIsArray( $active_plugins, 'Active sitewide plugins should be an array' );
+		$this->assertArrayHasKey( 'wp-multi-network/wpmn-loader.php', $active_plugins, 'Plugin should be auto-activated on new network' );
+	}
 }
diff --git a/wp-multi-network/includes/functions.php b/wp-multi-network/includes/functions.php
index a8afb59..d567aad 100644
--- a/wp-multi-network/includes/functions.php
+++ b/wp-multi-network/includes/functions.php
@@ -677,6 +677,13 @@ function add_network( $args = array() ) {
 		// Clean the network cache.
 		clean_network_cache( $new_network_id );
 
+		// Self-activate on new network.
+		$existing_plugins = get_network_option( $new_network_id, 'active_sitewide_plugins', array() );
+		if ( ! isset( $existing_plugins['wp-multi-network/wpmn-loader.php'] ) ) {
+			$existing_plugins['wp-multi-network/wpmn-loader.php'] = time();
+			update_network_option( $new_network_id, 'active_sitewide_plugins', $existing_plugins );
+		}
+
 		/**
 		 * Fires after a new network has been added.
 		 *