--- - |2+ Objective This is the first experimental evaluation of the effects of various regulations on the willingness of private school leaders to participate in a hypothetical school voucher program. Methods We use surveys to randomly assign different regulations to 2,958 private school leaders in Florida and ask them whether they would participate in a new private school choice program during the following school year. Results We received responses from 327 private school leaders. Relative to no additional regulations, our most conservative models find that open‐enrollment mandates reduce the likelihood that private schools are certain to participate by 17 percentage points or 70 percent. State standardized testing requirements reduce the likelihood that private schools are certain to participate by 12 percentage points or 46 percent. We find no evidence to suggest that the prohibition of copayment affects participation overall. We find limited evidence to suggest that regulations are more likely to deter higher‐quality schools.as measured by tuition levels and enrollment trends. Conclusion These results suggest that various regulations of private school choice programs come with costs and perhaps unintended consequences. - 'Social Science Quarterly, Volume 100, Issue 6, Page 2316-2336, October 2019. '