In this research, we present three studies on the development and validation of the Online Appearance-Relevant Peer Conversations Scale (OARPCS), a 12-item measure of (1) physical appearance and (2) life stressors as foci of online peer communications. In Study 1, young Chinese adults (N = 800) completed OARPCS items and measures of body image, Internet use, and general distress. Exploratory factor analyses supported the hypothesized two factor structure and within gender correlation analyses provided construct validity support. Study 2 replicated the EFA-derived OARPCS factor structure and validity further within confirmatory factor analyses of young adults from Chongqing (N = 750) and Macau (N = 994). Study 3 assessed the predictive validity of OARPCS dimensions in relation to prospective changes in cosmetic surgery consideration, eating disturbances and perceived stress over one year (N = 796). Independent of baseline responses on outcomes, baseline physical appearance and life stressor subscale scores, respectively, explained modest, significant variance in women's body image concerns and men's reported stress. Together, results underscored appearance-relevant content in online peer interactions as influences on body image and emotional status and provided psychometric support for a brief self-report measure of these factors.