The work described in this dissertation is focused on understanding the relationship between team adaptation and team cognition. Team adaptation represents the adjustment of behavior and cognition to the demands of novel situations or to changing circumstances. Team cognition, which refers to the interpretation of novel events or changing circumstances, represents a cornerstone of effective adaptation as it enables the team to assign meaning to the events and represent the process via which it can overcome them. There has been limited research devoted to studying the relationship between team adaptation and team cognition. In this work therefore, I take on the task of investigating these relationships more in-depth. To do this, I derive a series of theoretical propositions which I integrate in a theoretical framework and I empirically test some of these propositions in three studies. In the theoretical framework, I derive a contingency perspective on the relationship between team cognition and team adaptation by proposing that in order to effectively adapt to the demands of their environments the teams must develop certain cognitive characteristics that reflect the central features or dimensions of those environments. In line with this contingency perspective, I conduct three studies to investigate the role of team mental models, a team cognitive construct, for team adaptation. The work takes a longitudinal perspective, by emphasizing that team cognition develops over time and that this development is relevant for performance as opposed to cross-sectional influences. In the first study, I find that both dissimilar and similar mental models are relevant for the performance of project teams that meet changes but at different performance stages. Specifically, I find that at the onset of changes more dissimilar mental models are more favorable while at later performance stages more similar mental models are needed for the integration of the team strategies and to reach higher performance. In the second study, I find that dissimilar mental models can be represented as a long term team capability. Specifically, I find that mental models developed in the context of a changing or varied task affected the teams’ performance on a novel task. In the third study, I find that goal mental models that become more similar over time are more relevant for the performance of interdisciplinary student project teams, but that procedural mental models are less relevant for their performance. Overall, this work furthers the understanding of team adaptation by advancing a contingent perspective on the relationship between team cognition and team adaptation and by explicitly modeling context and time as elements of the study design that can bear on team outcomes.