While much research has focused on public-private differences in learning opportunities and achievement in high school, no studies have examined sector differences early in students' academic careers. In this study, I examine sector differences in learning opportunities and achievement in kindergarten. The analyses indicate: (1) learning opportunities vary across school sector, sometimes favoring public schools, sometimes not; (2) public school gains in achievement are either the same as private schools' or slightly greater; and (3) while learning opportunities have important effects on student learning, sector differences in learning opportunities explain some but not all of the sector differences in student learning.