Despite the growing attention to online social comparison, most studies have focused on the psycho-emotional implications of the behavior, leaving the identity implications ambiguous. Given the importance of identity development and the prevalence of social media use among emerging adults going through college transition, this study explored how social comparison on social media predicted identity processing styles among college freshmen. Short-term longitudinal survey data from 219 freshmen (M[subscript age] = 18.29, S.D. = 0.75; 74% female; 41% White, 38% Black) showed that social media social comparison was associated with higher perceived social pressure to be responsive on social media, which, in turn, predicted less utilization of the informational identity processing style; the comparison was also associated with higher levels of rumination, which predicted more use of the diffuse-avoidant style. The study expands the literature by showing that social comparison associates with not only affect, emotions, and evaluation of the self, as indicated by earlier research, but also how people approach their identity, which can have a long-term impact on the unity, stability, and growth of the identity.