Many variables affect teamwork and team performance on assignments, including student characteristics, the delivery mode, and instructors’ decisions about assignment design. In this study, the online assignment was a computer simulation of a competitive industry, the Business Strategy Game. Links between student teams’ performance and the delivery mode (online versus on-campus) and some of the instructors’ decisions regarding how to structure the simulation assignment were examined. Online delivery was correlated with significantly lower student team performance compared to on-campus delivery. On the other hand, while larger class size and smaller team size had negative effects on a student team’s performance for on-campus courses, class size, and team size did not matter online. In other words, team performance with online delivery was not constrained by class size or team size as it was on-campus. It was determined that instructors can improve team performance by making key choices when designing and delivering online simulation assignments. For on-campus delivery, allowing more class time for more frequent teamwork discussions was found to lead to higher team performance. Larger teams of 4-6 students outperformed smaller teams using on-campus delivery.