Nutrition, health and development during the first three years of life are at the foundation of human capital formation. Yet children growing up in poverty often experience low levels of stimulation and low quality of nutrition. Interventions that promote child stimulation and emphasize parent-child interactions providing opportunities to play and learn such as home visits and community groups have been identified as having great potential but there is little evidence of cost-effective interventions that can be implemented at scale in very poor environments. This study in India will develop evidence on the relative effectiveness of using home visits and group visits to help caregivers, usually mothers, support their children’s healthy development.