Catholic school tuition is not deductible on a U.S. income tax return. To be deductible, the school would have to provide post-high school education, according to the Internal Revenue Service.
If any portion of the tuition is for before-school or after-school care of a child who is under age 13 or is permanently disabled, that amount could qualify for the Child Care Credit. IRS Publication 503 states that education, no matter the child's age, is not eligible for this credit but that care while the parent is working is eligible. If both parents are living with the child, both would have to be working or looking for work to qualify. The credit is calculated on Form 2441.