This article provides a new model of tax compliance over the firm life course, focusing on the dynamics in the underlying motivations and capacities for tax compliance. We review and structure the relevant literature on the early life course of firms: the traditional stages of growth models and a less deterministic dynamic state model of developmental phases. Building on these insights on the changing nature of the firm and the role of the founder-entrepreneur, we construct a new model of tax compliance over the firm life course. We provide several potential avenues for future research as well as practical implications of our model.