diff --git a/woolist-phplist/includes/class-woolist-admin.php b/woolist-phplist/includes/class-woolist-admin.php
index 19a5446..55136b0 100644
--- a/woolist-phplist/includes/class-woolist-admin.php
+++ b/woolist-phplist/includes/class-woolist-admin.php
@@ -23,10 +23,17 @@ class WooList_Admin {
 		// Test connection admin-post handler.
 		add_action( 'admin_post_woolist_test_connection', [ $this, 'handle_test_connection' ] );
 
-		// Order page meta box (classic + HPOS).
-		add_action( 'add_meta_boxes', [ $this, 'add_order_meta_box' ] );
+		// Order page meta box — use screen-specific hooks so both classic and
+		// HPOS order edit pages are reliably targeted.
+		add_action( 'add_meta_boxes_shop_order', [ $this, 'register_meta_box' ] );
+		add_action( 'add_meta_boxes_woocommerce_page_wc-orders', [ $this, 'register_meta_box' ] );
 
-		// AJAX handler for the manual-subscribe button.
+		// WooCommerce Order Actions dropdown (works with classic + HPOS).
+		add_filter( 'woocommerce_order_actions', [ $this, 'add_order_actions' ] );
+		// Register one action handler per configured list (list IDs from options).
+		$this->register_order_action_handlers();
+
+		// AJAX handler for the manual-subscribe meta box button.
 		add_action( 'wp_ajax_woolist_manual_subscribe', [ $this, 'handle_manual_subscribe' ] );
 
 		// Admin assets.
@@ -120,20 +127,98 @@ class WooList_Admin {
 	// ── Order page meta box ───────────────────────────────────────────────────
 
 	/**
-	 * Register the meta box on both classic (shop_order) and
-	 * HPOS (woocommerce_page_wc-orders) order screens.
+	 * Called by add_meta_boxes_shop_order and add_meta_boxes_woocommerce_page_wc-orders.
+	 * The $post_or_order argument is passed by WC but not needed here.
 	 */
-	public function add_order_meta_box(): void {
-		foreach ( [ 'shop_order', 'woocommerce_page_wc-orders' ] as $screen ) {
-			add_meta_box(
-				'woolist_order_metabox',
-				__( 'phpList Sync', 'woolist-phplist' ),
-				[ $this, 'render_order_meta_box' ],
-				$screen,
-				'side',
-				'default'
+	public function register_meta_box( $post_or_order = null ): void {
+		// Determine the correct screen ID from the current hook name.
+		$screen = did_action( 'add_meta_boxes_shop_order' )
+			? 'shop_order'
+			: 'woocommerce_page_wc-orders';
+
+		add_meta_box(
+			'woolist_order_metabox',
+			__( 'phpList Sync', 'woolist-phplist' ),
+			[ $this, 'render_order_meta_box' ],
+			$screen,
+			'side',
+			'default'
+		);
+	}
+
+	// ── WooCommerce Order Actions dropdown ────────────────────────────────────
+
+	/**
+	 * Inject a "phpList: …" entry for each configured list into the
+	 * WooCommerce Order Actions dropdown (the select in the order sidebar).
+	 *
+	 * @param array $actions Existing order actions.
+	 * @return array
+	 */
+	public function add_order_actions( array $actions ): array {
+		foreach ( $this->get_configured_lists() as $list_id => $label ) {
+			$actions[ 'woolist_sync_' . $list_id ] = sprintf(
+				/* translators: %s: list label e.g. "Completed Orders" */
+				__( 'phpList: Add to %s list', 'woolist-phplist' ),
+				$label
 			);
 		}
+		return $actions;
+	}
+
+	/**
+	 * Register a woocommerce_order_action_{slug} handler for every
+	 * configured list at init time so WooCommerce can call them.
+	 */
+	private function register_order_action_handlers(): void {
+		foreach ( $this->get_configured_lists() as $list_id => $label ) {
+			$list_id_captured = $list_id; // explicit capture for the closure
+			add_action(
+				'woocommerce_order_action_woolist_sync_' . $list_id,
+				function ( $order ) use ( $list_id_captured ) {
+					$this->do_sync( $order, $list_id_captured );
+				}
+			);
+		}
+	}
+
+	/**
+	 * Shared subscribe logic used by both the Order Action and the meta box AJAX.
+	 *
+	 * @param WC_Abstract_Order $order   The order.
+	 * @param int               $list_id Target phpList list ID.
+	 * @return bool True on success.
+	 */
+	private function do_sync( WC_Abstract_Order $order, int $list_id ): bool {
+		$email    = $order->get_billing_email();
+		$order_id = $order->get_id();
+
+		if ( ! is_email( $email ) ) {
+			WooList_Logger::error( 'do_sync: order #' . $order_id . ' has no valid billing email.' );
+			return false;
+		}
+
+		WooList_Logger::info( 'do_sync: order #' . $order_id . '  email=' . $email . '  list_id=' . $list_id );
+		$result = $this->api->subscribe_email_to_list( $email, $list_id );
+
+		if ( $result['success'] ) {
+			// Add a visible note on the order so it's traceable in the order timeline.
+			$order->add_order_note( sprintf(
+				/* translators: 1: email, 2: list ID */
+				__( 'WooList: %1$s added to phpList list %2$d.', 'woolist-phplist' ),
+				$email,
+				$list_id
+			) );
+			return true;
+		}
+
+		$order->add_order_note( sprintf(
+			/* translators: 1: email, 2: list ID */
+			__( 'WooList: failed to add %1$s to phpList list %2$d. Check WooCommerce → Status → Logs.', 'woolist-phplist' ),
+			$email,
+			$list_id
+		) );
+		return false;
 	}
 
 	/**
@@ -247,19 +332,11 @@ class WooList_Admin {
 			wp_send_json_error( [ 'message' => __( 'Order not found.', 'woolist-phplist' ) ] );
 		}
 
-		$email = $order->get_billing_email();
-		if ( ! is_email( $email ) ) {
-			wp_send_json_error( [ 'message' => __( 'Order has no valid billing email.', 'woolist-phplist' ) ] );
-		}
+		WooList_Logger::info( 'Meta box manual subscribe: order #' . $order_id . '  list_id=' . $list_id . '  user#' . get_current_user_id() );
 
-		WooList_Logger::info(
-			'Manual subscribe: order #' . $order_id . '  email=' . $email . '  list_id=' . $list_id
-			. '  triggered_by=user#' . get_current_user_id()
-		);
+		$ok = $this->do_sync( $order, $list_id );
 
-		$result = $this->api->subscribe_email_to_list( $email, $list_id );
-
-		if ( ! $result['success'] ) {
+		if ( ! $ok ) {
 			wp_send_json_error( [
 				'message' => __( 'Subscription failed. Check WooCommerce → Status → Logs for details.', 'woolist-phplist' ),
 			] );
@@ -269,7 +346,7 @@ class WooList_Admin {
 			'message' => sprintf(
 				/* translators: 1: email address, 2: list ID */
 				__( '%1$s added to list %2$d.', 'woolist-phplist' ),
-				esc_html( $email ),
+				esc_html( $order->get_billing_email() ),
 				$list_id
 			),
 		] );