Mission Basilica San Buenaventura () is a Catholic parish in the Archdiocese of Los Angeles. The parish church in the city of Ventura, California, United States, is a Spanish mission founded by the Order of Friars Minor. Founded on March 31, 1782, it was the ninth Spanish mission established in Alta California (Or Nueva California) and the last to be established by the head of the Franciscan missions in California, Junípero Serra. Designated a California Historical Landmark, the mission is one of many locally designated landmarks in downtown Ventura.