Athletes, coaches, and sport psychologists alike believe emotions have a powerful influence on thoughts and actions. Athletes experience intense emotions before and during a race and mental preparation is focused on strategies intended to regulate emotions. Athletes wish to experience emotions that are desirable, emotions that they feel will help lead to better performance via mechanisms such as increasing energy, helping focus attention, and/or decision making. During performance, where intense emotions accompany fatigue, strategies such as changing pace or tolerating fatigue tend to be used. As such strategies to regulate emotions can help fatigue and performance management. This chapter will examine the role of emotions and emotion regulation in endurance sport.