A smart gateway, which plays a crucial role in a smart home, generally bridges the inside and outside home networks, as well as collaboratively manages the intelligent Internet of things (IoT) devices equipped in the smart home, due to it can convert different communication protocols, gather generated data from surrounding devices, and even conduct some local data processing tasks. In this survey, we first review the whole smart home research area with a focus on a framework based on edge computing and multiple intelligent agents. Then, relying on the time‐line and different metrics including quality of experience (QoE), artificial intelligence support, software‐defined network, and so on, we divide the evolution of smart gateways into three generations. Considering recent smart gateways mainly belong to the second generation, we further investigate and classify them into two categories from another perspective of user‐awareness and data‐awareness. Afterward, we discussed the key enabling technologies and components of smart gateways, such as operating systems, wireless communication protocols, and security. At last, we explore the challenges and trends of smart gateways and point out that maximizing QoE as well as data‐awareness is the key feature of future gateways. This survey has practical significance for building a smart home system, broadly speaking, even for constructing the IoT and smart space.