As more countries consider implementing multiple micronutrient supplements (MMS) policies and programs within country-level health systems, barriers to acceptability and uptake need to be systematically identified and addressed in order to enhance service delivery. This articles presents the results of formative research conducted by UNICEF, in partnership with Sight and Life Foundation and Pennsylvania State University, using a mixed-method approach. The results of which informed the context-specific design and implementation of MMS in four countries (Bangladesh, Burkina Faso, Madagascar, and Tanzania).