This article describes UNICEF’s support for high-burden countries in South Asia and sub-Saharan Africa in transitioning from iron folic acid (IFA) to multiple micronutrient supplements (MMS). It includes UNICEF ‘s theory of change with respect to MMS, which is adapted for individual countries. MMS offers an important opportunity to improve the quality of pregnancy care as well as survival and development outcomes for women and children using a contextualized and systems approach. Advocacy efforts make use of global evidence, national data, and align with national priorities. The introduction of MMS builds on formative research and is linked to the strengthening of relevant systems. Measuring and documenting success is critical to inform adjustments to implementation approaches and guide scale-up in other countries.