This chapter investigates the introduction of Medium-Term Revenue Strategies (MTRS) in developing countries as part of technical assistance for tax capacity building. The MTRS concept was devised by the Platform for Collaboration on Tax and is supposed to be a holistic high-level roadmap for tax policy reform around which civil society and external aid donors can coordinate. Tax capacity building for domestic resource mobilization has become a crowded governance field over the last decade with multiple bilateral and multilateral partners involved, sometimes in the same country. While there have been multiple high-level coordination efforts, within-country coordination is still lacking. As such, we investigate the concept’s usefulness as a coordination tool for donors to ensure their assistance is matched with a country’s needs and preferences. We also critically examine the concept’s potential pitfalls and deficiencies in terms of scope and ambition, partners, and legitimacy. We conclude that if the MTRS is evaluated as it is intended, an additional tool in the larger toolbox of coordination in the tax capacity building regime, the concept holds promise but calls for close scrutiny to ensure that they are truly country-owned and country-specific roadmaps.