Children from historically marginalized racial/ethnic and socieconomic groups on average, score lower on widely used assessments of academic, executive functioning, and social-emotional skills at kindergarten entry, but the extent to which these differences are shaped by exposure to early schooling is unclear. Using data from a public prekindergarten and kindergarten program in Boston, we leverage a seasonal comparison design to examine how patterns change during the school year relative to summer periods. Although trends vary somewhat by the skill domain and groups compared, we largely find that exposure to early schooling is compensatory or neutral in shaping inequality. This suggests that prekindergarten and kindergarten together contribute to more equitable outcomes than would otherwise be expected in the absence of schooling. However, we find no evidence of systematic differences in access to high-impact classroom processes, which leaves open the question of which aspects of early schooling are most associated with declining inequality. (author abstract)