Passion drives sport consumption, but we lack valid relevant measures of passion. The results of two studies provide evidence of a reliable and valid multiple-item passion scale that may be used in the study of sports-related consumption behavior. In Study 1 a multi-item fan passion scale was compared with established social identification fan classification scales to provide evidence of discriminant and predictive validity. Because the passion scale outperformed other relevant fan classification measures, in Study 2 the fan passion scale was compared with current single-item measurement practices employed by National Football League and Major League Baseball teams, and some academics, to classify fans. Findings confirmed the veracity of the multi-item passion measure over categorical and interval fan avidity measures used by leagues and syndicated research providers. Taken together, the studies validate an accurate measure of fan passion that may be used to segment and predict fan behaviors, including consumption of traditional media (television, radio, news, and the team’s website) and consumption of the team’s official social media outlets.