AJAX enhances user experience by enabling dynamic updates without page reloads. WordPress provides built-in AJAX handling through admin-ajax.php. Register AJAX actions using wp_ajax and wp_ajax_nopriv hooks. Use wp_localize_script to pass the AJAX URL and nonce to JavaScript. Always verify nonces in PHP handlers for security. Return data using wp_send_json_success or wp_send_json_error. Handle both authenticated and public requests appropriately. Implement proper error handling and loading states. Test AJAX functionality thoroughly across different scenarios. This technique creates more responsive, modern interfaces.