Ever since the idea of buffers was incorporated in wireless communications, buffer‐aided relaying has become an emerging breakthrough in the world of transmitting and receiving signals. Equipping the relays with buffers adds a new degree of freedom capable of enhancing numerous quality‐of‐service (QoS) metrics including throughput, outage probability, power efficiency and physical‐layer security. The QoS enhancement is achieved by compromising the end‐to‐end delay that is inflicted by storing the packets in the relays' buffers until a suitable source–relay or relay–destination link is selected. In this context, the selection of a relay for transmission/reception is important since it governs the QoS‐delay trade‐off that can be contemplated. In this survey, the authors review and analyse various link selection protocols in buffer‐aided relaying systems. These relaying strategies are categorised and contrasted according to their performance levels, limitations, applications, system model assumptions and complexity. Finally, they discuss current challenges, and highlight future research directions.