We review the empirical research on Free/Libre and Open Source Software (FLOSS) development and assess the state of the literature. We develop a framework for organizing the literature based on the input-mediator-output- input (IMOI) model from the small groups literature. We present a quantitative summary of articles selected for the review and then discuss findings of this literature categorized into issues pertaining to inputs (e.g., member characteristics, technology use and project characteristics), processes (software development and social processes), emergent states (e.g., trust and task related states) and outputs (e.g. team performance, FLOSS implementation and project evolution). Based on this review, we suggest topics for future research, as well as identifying methodological and theoretical issues for future inquiry in this area, including issues relating to sampling and the need for more longitudinal studies.