Cotton is a pivotal industrial crop, mainly cultivated for producing natural textile fibers. Considering its versatile capacity, cotton industry occupies indispensable strategic position at the national level. With the intensified greenhouse effect, the frequent and continuously occurring high temperature weather severely limited the cotton production in China and in the world. In the last decade, research groups have made visible progress in investigating the response of cotton to high temperature stress in order to breed high temperature tolerant cultivars to reduce yield loss. This review summaries the advances mainly including: (1) effective evaluation systems of high temperature tolerance performance in cotton; (2) genetic, physiological and biochemical mechanisms of high temperature tolerance in cotton; (3) high temperature tolerant germplasm innovation of cotton and breeding practice. We expect to raise questions and suggestions for cotton high temperature tolerance research, germplasm innovation and breeding practice in future.