Prior research estimating the effect of Catholic schooling has focused on high school, where evidence suggests a positive effect of Catholic versus public schooling. In this article, we estimate the effect of attending a Catholic elementary school rather than a public school on the math and reading skills of children in kindergarten through fifth grade. We use nationally representative data and a set of matching estimators to estimate the average effect of Catholic schooling and the extent to which the effect varies across educational markets. When we use public school students nationwide or within the same county to provide a counterfactual estimate of how Catholic school students would have performed in public schools, we find strong evidence indicating that Catholic elementary schools are less successful at teaching math skills than public schools (Catholic school students are 3-4 months behind public school students by third and fifth grade), but no more or less successful at teaching reading skills. Moreover, unlike prior research, we find no consistent evidence that the effects of Catholic schooling vary substantially by race or urbanicity, though our power to detect such differences is weak. (Contains 7 tables, 2 figures and 17 footnotes.)