Adequate nutrition during their first 1,000 days is necessary for children to grow and develop to their full potential. Alive & Thrive (A&T), a study sponsored by the Bill & Melinda Gates Foundation, contributes to better nutrition during the first 1,000 days by promoting improved infant and young child feeding (IYCF) practices. In its first 5 years, A&T successfully delivered high-impact IYCF interventions at scale in three countries. During the second phase, A&T will expand its effort to several new countries, including Nigeria. The target states in Nigeria are Lagos and Kaduna. As part of A&T’s efforts in Nigeria, an external evaluation will be conducted to rigorously measure the impact of two different A&T intervention models as adapted in Kaduna and Lagos states. These interventions will use different types of communication strategies, including interpersonal communication, community mobilization, and mass media communication. The two intervention models will include community mobilization and will differ in the interpersonal communication strategy. The two strategies are (1) an intensive interpersonal communication intervention with a full array of messages on IYCF and multiple interactions with women in the target group, and (2) a streamlined interpersonal communication approach with a more targeted set of messages and fewer interactions. These two interventions will be compared with mass media communication on infant and young child feeding, which will be provided throughout the two states. RTI will assist in conducting the impact evaluation of A&T.