Recent information systems research has studied various aspects of virtual teams. However, the foundations and theoretical development of virtual team research remain unclear. We propose that an important way to move forward is to accelerate the process of theorizing and theory appropriation. This article presents an in-depth analysis of the current state of the art of theory application and development in virtual team research. We identify the frequency, pattern of use, and ontological basis of 25 virtual team-relevant theories. A researcher’s tool kit is presented to promote future theory application and appropriation. The tool kit consists of a descriptive and analytical database of theories relevant for virtual team research. We also present a framework for appropriating virtual team theories based on seven criteria. A detailed example demonstrates the application of the theory appropriation framework. The article contributes to the literature by presenting the state of the art of theory use in virtual team research and by providing a framework for appropriating reference-discipline theories.