Mater Dei High School is a private, Catholic, co-educational school in Santa Ana, California, administered by the Diocese of Orange, and opened in 1950 as the first Catholic high school in Orange County. It is nationally renowned for its athletics, particularly football, ranking #1 for "best high schools for athletes" on Niche, with over 68% of students participating in 25 sports and a total of 90 CIF, state, and national championships. The Monarchs' football team has won national titles in 1994, 1996, 2017, 2018, 2020, 2021, and 2023, plus the 2024 state title, and counts John Huarte, Matt Leinart, and Bryce Young—all Heisman Trophy winners—among its alumni. Growing from just 111 students at its founding, it became the largest Catholic high school west of Chicago by the 1970s, though overcrowding persisted until nearby schools opened in the late 1980s. The school has faced controversy, including 2021 lawsuits over hazing and an attack in the football program (one dismissed in 2023) and a 2022 suit alleging sexual assault by a former coach, which led Bishop Kevin Vann to publicly defend the school's leadership. Beyond football, it has produced professional athletes like soccer star Robbie Rogers and MMA fighter Tiki Ghosn, as well as ten Olympians, solidifying its reputation as a top athletic powerhouse.