The purpose of this study was to examine the effect of case studies on learning outcomes, attitudes toward instructions, and team shared mental models (SMM) in a team-based learning environment in an undergraduate educational psychology course. Approximately 105 students who participated in this study were randomly assigned to either a case-study method or a knowledge-representation method. Students in the case-study treatment group received a case study after instruction, while students in the knowledge-representation treatment group engaged in an activity that did not involve problem solving. It was hypothesized that students in the case-study group would have higher learning outcomes scores, higher attitudes scores, and greater team SMM than students in the knowledge-representation group. Overall, the case-study method was effective as indicated by generally higher learning outcomes and more positive attitudes for the case-study treatment group as compared to the knowledge-representation group. It might be important to consider the order in which each of the instructional methods is given.