CTSO has operated since 1999 from the diocesan offices at 192 S. Stone Avenue downtown and reports more than 55,000 scholarships awarded at more than 40 schools. The Department of Revenue credits it with $211.1 million in donations since the program began and 3,502 students helped in fiscal 2025, which makes it one of the larger STOs in the state.
The Diocese of Tucson runs 23 Catholic schools across six counties with roughly 6,700 students from preschool through high school, according to Superintendent Sheri Dahl's January 2025 column. CTSO cites a 99% graduation rate at the diocese's Catholic high schools, and Salpointe Catholic received more original-credit scholarships in fiscal 2025 than any other school in Arizona: 918.
One practical note for this site: the STO lists we matched in October 2026 did not include CTSO's school list, so a Catholic school's profile here may show only APSTO, IBE or School Choice Arizona. CTSO says it serves more than 40 schools, so ask your Catholic school's office whether it participates and how and when to apply.
CTSO scholarships follow the same ESA rule as any STO. A family that signs an ESA contract for a child cannot also take a CTSO award for that child in the same year. Many Catholic families with several children split the decision, using CTSO aid for a high schooler and the ESA for a younger sibling, or the other way around.
Parishioners can also help directly. A Tucson couple filing jointly can direct up to $1,570 of 2026 state tax to CTSO under the original credit and another $1,561 under the switcher credit, and corporations can give through the low-income and disabled/displaced corporate credits.
Combining it with other sources
In Tucson the main decision is ESA or STO for each child each year; the two can't be combined for the same student. A school's own discounts, such as parish, member or sibling rates, lower the bill and can usually sit alongside either path.