Save the Children has developed a low-cost and potentially scalable early stimulation program that delivers actionable messages to mothers and other caregivers that show them how to interact and play with young children. American Institutes for Research (AIR) and its research partners at Data International, the International Centre for Diarrhoeal Disease Research, Bangladesh, and Minhaj Mahmud, the head of research of BRAC Institute of Governance of BRAC University, are conducting a cluster-randomized control trial to evaluate the impact of the early stimulation program in the regions of Satkania, Muladi, and Kulaura in Bangladesh. The study is also receiving advice from a Technical Advisory Board consisting of child development and nutrition specialists and government officials in Bangladesh. In this evaluation, community clinics within the same union are randomly assigned to either receive the Save the Children intervention or not. Data on individual child outcomes and family stimulation behavior are collected from households within the catchment areas of these community clinics. Data from service providers operating within each community clinic’s catchment area are also collected. Seventy eight community clinics are participating in the study, with half receiving the intervention (the treatment group) and half not receiving it (the control group). Thirty three households with children between 3 and 18 months of age residing in the catchment area of each community clinic at the time of baseline data collection were randomly sampled, resulting in a total sample size of 2,574 households, half treatment and half control.