This study investigated gender differences in physical activity (PA) and social-cognitive theory (SCT) variables among Hispanics. Students (N = 298) completed measures assessing levels of PA and variables derived from SCT. Men reported greater PA than women. Men also reported having greater self-efficacy for PA, greater perceived ability to set Goals and make Plans for PA, and greater Expectancies that PA would produce psychological effects (e.g., reduced stress), improve their body image, and enhance their competitive ability. In addition, gender moderated associations between SCT variables and PA behaviors such that self-efficacy and self-regulation were the best predictors of PA among women (ß = 0.18, ß = 0.24, respectively), but body image was the strongest predictor of PA among men (ß = 0.15). The results are discussed in the context of promoting PA in this population.