College students (N = 90) reported their pro-environment behaviors as well as their pro-environment intentions, their explicit and implicit attitudes about the environment, and their knowledge about environmental issues. Intentions and knowledge significantly and independently predicted behavior. Environmental knowledge was not significantly related to attitudes. Implicit and explicit attitudes were significantly but only moderately related. Only explicit attitudes, however, were strongly related to intentions, and intentions completely mediated the influence of explicit attitudes on behavior. Men were found to be more knowledgeable than women about environmental issues; older students had more favorable implicit and explicit environmental attitudes. This research suggests that knowledge about the environment and explicit attitudes influence behavior through different pathways, which may have implications for interventions seeking to increase environmentally friendly behavior.