Message queues and message brokers are both used for event handling in complex systems or at scale. While they have similar interfaces, their differences lie in delivery guarantees, scheduling, and coupling. Queues typically provide an ordered series of events with a 1-to-1 relationship between messages and workers, while message brokers allow multiple services to subscribe to a topic and offer different delivery guarantees. Both systems can be used together for handling delayed jobs, background jobs, and asynchronous functions in growing complexities.