The Childcare Supply Improvement Act of 2024 establishes a federal grant program to help states, Indian tribes, and tribal organizations expand childcare availability and strengthen the childcare workforce. States and tribes would receive grants to support two main activities: acquiring or improving childcare facilities through community development financial institutions, and providing quality improvement services such as licensing support, professional development for childcare providers, and business startup assistance. The bill reserves at least four percent of appropriated funds for Indian tribes and territories, while distributing remaining funds to states based on factors related to young children and school lunch participation. Grant recipients must conduct community needs assessments before spending funds and must use the money to supplement rather than replace existing childcare funding. The legislation authorizes whatever funding is necessary but does not specify a dollar amount or implementation timeline.