O'Connell College Preparatory School is a 4-year co-educational private, Catholic secondary school located in Galveston, Texas and serving the island and bay area of Galveston, Brazoria and Harris Counties.  It was founded in 1968 as a consolidation of Galveston Island's three existing Catholic high schools: Kirwin High School (Boys, founded in 1927) and Dominican High School (Girls, founded in 1882) and Ursuline Academy (Girls, founded in 1847) and is the only Roman Catholic high school in Galveston County.

In the fall of 1968, the religious orders operating the three schools agreed on consolidation as a means of continuing Catholic secondary education in Galveston, offering a broader curriculum than was possible in any of the three smaller high schools. Bishop John Morkovsky, S.T.D., approved the plan and appointed a Board of Trustees composed of laymen and priests representing all the parishes in Galveston County. The Board named the newly consolidated school after the Right Rev. Monsignor Daniel P. O’Connell, P.A., pastor of St. Mary’s Cathedral in Galveston from 1933 until his death in 1966, and a long time supporter of Catholic education.