This primer documents the work of members of the Market Development Approaches Working Group of the Reproductive Health Supplies Coalition in defining and implementing total market initiatives (TMI). A TMI in reproductive health is a process in which the suppliers and financers of reproductive health products and services from across sectors—public, nonprofit, and commercial—develop a common strategic framework for maximizing use of reproductive health products and services to improve equity, efficiency, and sustainability in the health system. In addition to defining the concept and providing practical examples, the paper discusses when TMIs should be implemented, the process for implementation, and what indicators should be used to measure their success.