Abstract Zinc tin nitride (ZnSnN₂) is one of the emerging ternary nitride semiconductors considered for photovoltaic device applications due to its attractive and tunable material properties and earth abundance of constituent elements. Computational predictions of the material properties sparked experimental synthesis efforts, and currently there are a number of groups involved in ZnSnN₂ research. In this article, we review the progress of research and development efforts in ZnSnN₂ across the globe, and provide several highlights of accomplishments at the National Renewable Energy Laboratory (NREL). The interplay between computational predictions and experimental observations is discussed and exemplified by focusing on unintentional oxygen incorporation and the resulting changes in optical and electronic properties. The research progress over the past decade is summarized, and important future development directions are highlighted.