In their 1989 article in the Journal of Sport & Exercise Psychology (JSEP), Hart, Leary, and Rejeski introduced both the construct of Social Physique Anxiety (SPA) and the Social Physique Anxiety Scale (SPAS). Both the construct and measure were immediately incorporated into the sport and exercise psychology literature, and have remained prominent over the last 20 years. Notably the article was published just one year after "Exercise" was added to the title of JSEP, which had been the Journal of Sport Psychology since 1979. Indeed, the article and particularly the SPAS promoted research on psychological dispositions and social cognitive factors in physical activity and exercise settings other than competitive sport. Although both state and trait anxiety were popular in sport psychology, and sport-specific measures had been developed, those measures and the related research focused on competitive anxiety and anxiety-performance relationships. Social physique anxiety emphasizes self-presentation and body image issues, and those issues are particularly relevant for less-than-elite participants in social settings. Research with the SPAS over the last 20 years indicates that social physique anxiety is related to self-perceptions and behaviors within exercise settings. Research confirms that SPAS scores are negatively related to self-esteen, body esteem and physical self-efficacy, and that SPA is higher in females than in males, and lower in athletes than in less active individuals. SPA has also been related to exercise behaviors including preferences for settings, although the results are not totally consistent, and situational factors play a large role. Continuing research is refining the construct and measurement of social physique anxiety, and advancing our understanding of its relationship to sport and exercise behaviors.