Appearance-related social anxiety has been identified as a relevant risk factor in the development of eating disorders (ED) and depression in young adults. However, less is known about the role that fitness-related social anxiety may play on the emergence of these two psychopathological conditions. The present study aimed to examine whether appearance/fitness social anxiety may independently contribute to explaining the increased risk of ED and depressive symptoms in young adults. A total of 545 undergraduate students (46% women, M  = 21.36, SD  = 2.93) recruited in two Spanish public universities completed a self-reported questionnaire. After controlling for self-reported BMI and appearance-related social anxiety, the results from the regression analyses revealed that fitness-related social anxiety positively and significantly (p < 0.05) contributed to explaining both the risk of ED (in women and men) and depressive symptoms (in women). The inclusion of the interaction term within the appearance/fitness-related term positively contributed to explaining additional variance for both the risk of ED and depressive symptoms in men, but not in women. The regression models explained 48% (women) and 35% (men) of the ED risk and 25% (women) and 19% (men) of depressive symptoms. These findings suggest that not only appearance, but also fitness-related social anxiety experiences may contribute to explaining the emergence of ED and depression in young adults.