This study investigates the ways in which medical students' achievement goal orientations (AGO) affect their perceptions of learning and actual learning from an online problem-based learning environment, Calibrated Peer Review™. First, the tenability of a four-factor model (Elliot & McGregor, 2001) of AGO was tested with data collected from medical students (N = 137). Then, a structural regression model relating the factors of AGO to students' perceptions of grading fairness, judgments of learning, and scoring accuracy was tested. The results indicate that student engagement and success in diagnosing a patient's presentation using a peer feedback-rich web-based PBL environment is somewhat dependent on student motivation. Theoretical and practical implications, in terms of problem-based learning environments in medical education, are discussed.