A theoretical framework serves as a roadmap for the implementation and application of a complex, health promotion intervention; is used to test hypotheses; and guides analysis and evaluation of the intervention. The purpose of this article is to demonstrate how a theoretical framework was developed and used to guide the implementation of Healthy Beginning Initiative (HBI) to promote uptake of HIV services in a low-income country. We used the guide for developing a theoretical framework published in Health Promotion Practice. Developing the theoretical framework included seven steps: (1) identifying the essential elements of the intervention; (2) identifying the variables and the context; (3) listing the postulated mechanisms, mediating variables, and postulated outcomes; (4) identifying existing theoretical models supporting the theoretical framework underdevelopment; (5) scripting the theoretical framework into either a figure or sets of statements; (6) conducting content and face validation of the theoretical framework; and (7) revising the theoretical framework. The theoretical framework was developed and used to evaluate HBI’s impact on HIV testing, linkage to care and retention in care for pregnant women, their male partners, and newborns. The theoretical framework will also be adapted for other screenings and other settings while remaining true to the essential elements of HBI.