The Publish-Subscribe Model is a messaging pattern commonly used in IoT systems. In this model, devices (publishers) send messages to topics, while other devices (subscribers) receive messages from those topics. This approach decouples senders and receivers, allowing for more flexible and scalable communication. The model is widely used with protocols like MQTT, where brokers manage the distribution of messages. It helps reduce unnecessary traffic, as devices only receive the data they subscribe to. This makes it highly efficient for large networks with many IoT devices.