Early childhood is a critical period for child development, and several studies find high returns to formal early schooling (e.g., pre-K) in developed countries. However, there is limited evidence on whether formal pre-primary schooling is an effective model in developing countries. We study the impacts of attending kindergarten on child development in Karnataka, India, through a randomized evaluation. We partnered with a private kindergarten provider to offer two-year scholarships to children in low-income families. Children who attend the partner kindergarten due to the scholarship experience a 0.8 standard deviation gain in cognitive development. Some children induced to attend the partner kindergarten would not have attended kindergarten, while others would have attended a different kindergarten. We use machine learning techniques to predict each child’s counterfactual activity and then estimate separate treatment effects for each type of switcher. We find that the short-run effect on cognition is driven mostly by children who would have otherwise not attended kindergarten. About 40% of the effect on cognitive development persists through first grade, with more persistence for higher-order thinking skills. In contrast, we find no effects on socioemotional development, which could be due to most children interacting with other children in daycare centers even if they do not attend kindergarten.