Fenwick High School is a private Catholic college preparatory school located in Oak Park, a town in Cook County, Illinois, United States. Fenwick was founded in 1929 and is a ministry of the Province of St. Albert the Great (Dominican Friars). It is the only school directly operated and staffed by the Order of Preachers (Dominican friars) in the United States. It is named in honor of the first bishop of Cincinnati, Dominican friar Edward Dominic Fenwick, O.P..

Retired Marine Corps Col. Otto J. Rutt, a Harvard University graduate and Fenwick alumnus, became the school's first lay president in November 2024.