“Self-objectification” is the internalization of an observer’s perspective on the self. It has been linked to a range of maladaptive outcomes among adolescents. This study introduced examined the implications of social media self-objectification (“SMSO”), in particular, for adolescents’ body image and mental health. The subject population consisted of 226 adolescents in one ethnically heterogeneous US high school (mean age = 16.25, 58.4% female). Participants reported their daily time spent on social media and their body surveillance, body comparison, disordered eating symptoms, depressive symptoms, and disrupted flow. This study provided evidence that SMSO is associated with aspects of adolescent mental health (namely, disordered eating symptoms, depressive symptoms, and disrupted flow) previously associated with traditional self-objectification. This establishes SMSO’s reliability and validity.