In this article, we build on theories of team adaptation by exploring the role of team members' cognitive knowledge structures in team adaptation to a changing task context. We introduce the notion of mental model updating as the extent to which team members update their mental models in reaction to a change in the task situation. In a laboratory study we investigate the relations between initial mental model similarity and accuracy, team mental model updating, the development of novel interaction patterns, and postchange team performance. The results indicate that mental model updating is positively related to postchange team performance. Also, team adaptation patterns accounted for the effect of mental model updating on postchange team performance. We did not find evidence for a positive relation between initial mental model similarity and accuracy and mental model updating.