Emotions are multifaceted subjective feelings that reflect expected, current, or past interactions with the environment. They involve sets of interrelated psychological processes, encompassing affective, cognitive, motivational, physiological, and expressive or behavioral components. Emotions play a fundamental role in human adaptation and performance by improving sensory intake, detection of relevant stimuli, readiness for behavioral responses, decision-making, memory, and interpersonal interactions. These beneficial effects enhance human health and performance in any endeavor, including sport, work, and the arts. However, emotions can also be maladaptive. Their beneficial or maladaptive effects depend on their content, time of occurrence, and intensity level. Emotional self-regulation refers to the processes by which individuals modify the type, quality, time course, and intensity of their emotions. Individuals attempt to regulate their emotions to attain beneficial effects, to deal with unfavorable circumstances, or both. Emotional self-regulation occurs when persons monitor the emotions they are experiencing and try to modify or maintain them. It can be automatic or effortful, conscious or unconscious. The process model of emotion regulation provides a framework for the classification of antecedent- and response-focused regulation processes. These processes are categorized according to the point at which they have their primary impact in the emotion generative process: situation selection (e.g., confrontation and avoidance), situation modification (e.g., direct situation modification, support-seeking, and conflict resolution), attentional deployment (e.g., distraction, concentration, and mindfulness), cognitive change (e.g., self-efficacy appraisals, challenge/threat appraisals, positive reappraisal, and acceptance), and response modulation (e.g., regulation of experience, arousal regulation, and expressive suppression). In addition to the process model of emotion regulation, other prominent approaches provide useful insights to the study of adaptation and self-regulation for performance enhancement. These include the strength model of self-control, the dual-process theories, the biopsychosocial model, the attentional control theory, and the individual zones of optimal functioning model. Based on the latter model, emotion-centered and action-centered interrelated strategies have been proposed for self-regulation in sport. Within this framework, performers identify, regulate, and optimize their functional and dysfunctional emotions and their most relevant components of functional performance patterns.