O'Dea High School is a Catholic all boys high school founded in 1923 and is located in Seattle's First Hill neighborhood. The school is named after Edward John O'Dea who was bishop of Seattle when the school was built. O'Dea is a part of the Archdiocese of Seattle.

Of its 480 students in four grades in 2022, 56% were Catholics, 53% were Caucasian, 16% were African American, and 19% were multi-racial. There are 36 instructors and the student-teacher ratio is 14 to 1. The tuition at O'Dea High School for the 2023-2024 school year was $19,555; the school provides over $2 million in financial aid every year.