Popularity in adolescence has been of interest to researchers for decades—oft described and conceptualized as social power, yet few studies have investigated the overlap between popularity and social power outside of Vaillancourt and Hymel (2006). This dissertation explores the extent to which popularity is synonymous with social power by examining three research questions: (1) to replicate research done by Vaillancourt and Hymel (2006), (2) to measure the convergence between an indirect construct of power in the vein of Vaillancourt and Hymel with a new, sociometrically consistent, direct measure of power, and (3) to look at the unique contributions of power to the prediction of peer-reported prosocial and antisocial behaviors. This study used a longitudinal middle school sample of 314 7th and 8th graders. Sociometric and self-report data were collected as part of a larger research project in the Fall of 2019. Results suggest that while Vaillancourt and Hymel’s original model was sound, a single, direct measure of power most strongly explained the variance of popularity above and beyond the indirect measures of power. The effects of power on prosocial and antisocial are moderated by gender after controlling for popularity. Keywords: Popularity, Social Power, Adolescence, Measurement