Tomato heat tolerance: Progress and prospects

•Various indicators used to evaluate heat tolerance in tomato plants are summarized.•The current state of germplasm and quantitative trait loci related to tomato heat tolerance are reviewed.•The physiological mechanisms and molecular basis of tomato heat tolerance are discussed.•The main challenges and future research efforts required for tomato heat tolerance are proposed. Global warming is one of the most concerning challenges that human beings are facing. The occurrence and intensity of heat stress events are expected only to increase, with a major negative impact on agricultural production systems. Tomato is one of the most important vegetable crops worldwide, but it is highly sensitive to heat stress. Genetic improvement of heat tolerance will be critical for the sustainable production of tomato. Here, we provide an update on various aspects of tomato heat stress response and tolerance, including the various indicators used in heat tolerance evaluation, germplasm and quantitative trait loci, physiological mechanisms and molecular basis of tomato heat tolerance. Finally, we highlight the main challenges and the required future efforts in tomato heat tolerance research.