This report provides a first-of-its-kind descriptive summary of private school expenditures. It includes comparisons of expenditures among different types and affiliations of private schools, and it also compares those expenditures with public school expenditures for districts in the same state and labor market. Results indicate that (1) the less-regulated private school sector is more varied in many key features (teacher attributes, pay and school expenditures) than the more highly regulated public schooling sector; (2) these private school variations align and are largely explained by affiliation--primarily religious affiliation--alone; and (3) a ranking of school sectors by average spending correlates well with a ranking of those sectors by average standardized test scores. (Contains 5 tables and 22 figures.)