Do market-based policies, like school vouchers, that provide an exit option enhance or diminish parental involvement? I examine this question using original survey data from parents participating in the Milwaukee Parental Choice Program, the nation's oldest urban voucher program. Voucher students were matched to a set of public school students based on Census tract, test scores, and demographic factors. I find voucher parents say that they are more willing than public school parents to use voice over exit. Further, voucher parents report being more involved in school-based activities or participatory coproduction, while public school parents report participating in more home-based education activities or independent coproduction. Multiple mechanisms inform these relationships. Voucher schools may be more receptive to parental involvement, and the religious nature of some voucher schools may promote participatory coproduction.