Dual Language Learners (DLLs) are young children who have at least one parent who speaks a language other than English at home, meaning when they enroll in English-speaking preschool, kindergarten, or other early childhood programs, their brains are using multiple language systems that are developing at different rates. Research shows that to effectively support DLLs' early learning trajectories, the design of these programs must be responsive to their particular cognitive, socioemotional, and language development needs. Nationwide, there are 7.1 million young children ages 0 to 5 who are DLLs, comprising 33 percent of all children in this age group. This large population is extremely diverse, bringing language skills and cultural assets among other important strengths to their schools and communities. These children are also disproportionately likely to face multiple risk factors that make them important targets for preschool and other early childhood services. This fact sheet highlights key characteristics of the country's DLL children and the households in which they reside, underscoring both their diversity and certain factors that may hinder their access to early childhood services. These characteristics should be considered in the design and implementation of early childhood services to ensure they are equipped to support the well-being and future success of all children and their families. This information is based on Migration Policy Institute (MPI) analysis of data from the U.S. Census Bureau's American Community Survey (ACS) for the 2019-23 period, pooled.