The present study examined an early childhood music intervention designed to promote children’s self-regulatory skill development. The participants were 191 children ages 3-5 years old who faced economic hardship. A quasi-experimental, stepped-wedge design that included four preschools and 3 study years facilitated comparing across the school year children who received preschool programming as usual (n = 43) with those who additionally received the music intervention (n = 148). Well validated child assessments measured the inhibitory control aspect of self-regulation, as well as receptive vocabulary, and a parent interview measured demographic covariates. (author abstract)