An area of inquiry that has largely been ignored in scientific studies in the field of sport psychology/motor performance is the subdiscipline of psychology called psychophysiology. This subdiscipline, which is concerned with inferences of psychological processes and emotional states from an examination of physiological measures, is rich in methodological and theoretical insights that could improve research and practice within sport psychology/motor performance. The current methodological and theoretical issues in psychophysiology are first reviewed and then specifically related to recent sport studies that demonstrate their applicability to the enhancement of both theoretical and applied aspects of sport.