Celery Beat is a scheduler that enables the execution of periodic tasks in Celery. It operates alongside the Celery worker and schedules tasks to run at specified intervals. To use Celery Beat, you start it as a separate process (celery -A your_project_name beat) and configure periodic tasks in your Celery tasks module. These tasks can run at fixed intervals, specified using cron-like expressions, providing a convenient way to automate recurring tasks within your application.