Using a biopsychosocial model as a framework, the aim of this study was to investigate the associations of biological, psychological, and sociocultural variables with drive for muscularity in weight-training men. As predicted, these variables explained a significant amount of the variance in drive for muscularity and its subscales. In support of the hypotheses, internalization of media body ideals, dissatisfaction with muscularity, and aspects of self-esteem, which include physical attractiveness and fitness, as well as age and FFMI, each demonstrated significant predictors for weight-training men’s drive for muscularity. On the contrary, dissatisfaction with body fat, global self-esteem, performance-related self-esteem, and stressful peer experience were not significantly associated with drive for muscularity.