As entrepreneurship research has matured, scholars have increasingly recognized that the formation of new ventures is commonly accomplished by teams as opposed to lone entrepreneurs. Over the past two decades, the upper echelons perspective has served as the primary lens for investigating new venture team functioning and performance. However, researchers have begun to move beyond the relationship between team characteristics and team outcomes, to explore intermediary mechanisms that more precisely explain how team inputs lead to team effectiveness. In this article we apply an inputs-mediators-outcomes framework, which has served as a foundation for teams research in organizational behavior over the past 50 years, to first organize and review prior work on new venture teams, and then to provide a roadmap for future research. By integrating the upper echelons approach from strategic management with the inputs-mediators-outcomes framework from organizational behavior, we clarify what is known about new venture teams and shed light on important issues that could help the field of entrepreneurship to develop a more comprehensive understanding of why some new venture teams, but not others, achieve successful outcomes.