All tax credit scholarship (TCS) programs are state programs. States develop program policies and requirements, including establishing the roles and responsibilities of scholarship granting organizations (SGOs) and participating private schools. The President's fiscal year 2020 budget request included a proposal for federal tax credits for donations to state-authorized SGOs. The Government Accountability Office (GAO) was asked to review key characteristics related to accountability in state TCS programs that can fund K-12 educational expenses. This report examines (1) key requirements state TCS programs have chosen to establish for SGOs; (2) key requirements for private schools participating in state TCS programs; and (3) how selected states implement TCS programs and assess whether SGOs and participating private schools are following key state requirements. GAO identified key requirements states may choose to establish related to accountability for SGOs and schools based on relevant research and prior work. GAO also reviewed program documents from all 22 TCS programs to identify whether they had these key requirements as of school year 2018-2019 and then verified this information with state program officials. GAO did not conduct an independent review of state laws and regulations. GAO visited Arizona, Florida, and Pennsylvania, which have the largest TCS programs. In each of these states, GAO reviewed program documents and interviewed officials at state agencies and staff at selected SGOs and private schools (selected to provide variation in size and other characteristics).