Elevated temperature can impact dairy cows in many aspects, leading to a decline in productivity and ultimately the profitability of the industry. There is a need to breed for heat tolerant dairy cattle to mitigate these impacts. This chapter outlines technologies to breed for more heat tolerant dairy cattle, exploiting either between or within breed genetic variation in the trait. Finally, the chapter discusses future perspectives on the use of different tools to achieve accelerated improvements of this important trait, and provides detailed guidance on further reading in this area.