Most college students do not meet physical activity (PA) guidelines, and ethnic disparities exist. The present study examined the utility of the theory of planned behavior (TPB) in explaining PA intentions and behavior in black and white college students and whether any TPB relationships were moderated by ethnicity. Black (n = 170) and white (n = 180) students completed a baseline TPB questionnaire and PA assessment 2 weeks later. Hierarchical latent variable regression analyses showed that affective attitude, subjective norm, and perceived behavioral control (PBC) were significant predictors of intention for both ethnic groups, whereas the PBC-intention relationship was significantly stronger for white students. Intention significantly predicted PA for both ethnic groups. Furthermore, common and ethnic-specific beliefs were identified. (Contains 4 tables.)