How to Automatically Tag Purchased Products in WooCommerce

You can automatically tag purchased products in WooCommerce by hooking into the thank-you page action and assigning a predefined product tag to every item in the order — useful for marking bestsellers, running tag-based promotions, or building custom “previously purchased” logic.

Why Auto-Tag Products on Purchase

• Differentiating purchased products from never-sold ones for reporting or targeted discounting
• Powering a custom shortcode or widget that shows “popular” or “best-selling” products based on real sales activity
• Feeding tag-based logic elsewhere on the site (like excluding sold-out-often items from a promo) without manual tagging

Step 1: Create the Tag and Note Its ID

Create a product tag (e.g. “Customer Favorite”) under Products > Tags first, and note the numeric term ID shown in the URL when editing it.

Step 2: Auto-Assign the Tag on Purchase

/** Tag every purchased product with a "Customer Favorite" tag after checkout (on the thank-you page) */
add_action( 'woocommerce_thankyou', 'tag_products_as_customer_favorite' );

function tag_products_as_customer_favorite( $order_id ) {
    $order = wc_get_order( $order_id );
    if ( ! $order ) return;

    $favorite_tag_id = 4821; // Replace with your tag's term ID

    foreach ( $order->get_items() as $item ) {
        $product = wc_get_product( $item->get_product_id() ); // The parent product: variations can't hold tags
        if ( ! $product ) continue;

        $existing_tags = $product->get_tag_ids();
        if ( ! in_array( $favorite_tag_id, $existing_tags, true ) ) {
            $product->set_tag_ids( array_merge( $existing_tags, array( $favorite_tag_id ) ) );
            $product->save();
        }
    }
}

Troubleshooting

Tag Doesn’t Get Applied

Double-check the term ID matches the tag you created — using the tag’s name or slug instead of its numeric ID is the most common mistake, since set_tag_ids() expects integers.

Tag Gets Applied Multiple Times on Repeat Orders

The in_array() check already prevents duplicate entries in the tag array, so re-purchasing the same product won’t create redundant tags — it simply confirms the tag is still present.

Frequently Asked Questions

Conclusion

Automatically tagging purchased products in WooCommerce is a short snippet on the thank-you hook that keeps your tag-based logic (promotions, reporting, custom shortcodes) up to date without manual tagging after every sale.

See also How to Display All Products Purchased by a Customer in WooCommerce. Then read How to Count Product Purchases by ID With a Shortcode.

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