This paper examines voluntary contributions to public education via charitable school foundations, booster clubs, parent teacher associations, and parent teacher organizations. We use panel data on school-supporting charities with national coverage from 1995 to 2010, which we geocode and match to school districts. We document the meteoric rise of school-supporting nonprofits during this panel, and then estimate a series of regression models to examine the distributional consequences of voluntary contributions. We find relatively large districts have higher probabilities of receiving revenues from a school-supporting nonprofit but the level of per-pupil voluntary contributions declines with student enrollment. In addition, we find school districts with higher endowments have higher probabilities of being served by at least one school-supporting nonprofit and higher levels of per-pupil contributions. Finally, we find no evidence that impressive recent growth in the number and financial size of these school-supporting charities relates to reductions in the public financing of schools.