Virtually all of the cells, tissues and organs in plants age, senesce and eventually die. Senescence is regarded as an evolutionarily acquired process that is critical for plant fitness, and understanding its detailed molecular nature is not only fundamental but also pivotal for the improvement of crop yield and postharvest storage. Impressive progress has been made in revealing new molecular regulatory mechanisms in recent years. In this special issue, reviews span this emerging knowledge - derived from unique biological processes in different types of plant senescence - and highlight key molecular pathways and network-based regulatory mechanisms, as well as their evolutionary implications. The issue also addresses future research perspectives, including new technologies and approaches.