Alleman Catholic High School is a private, Catholic high school in Rock Island, Illinois. It is located in the Diocese of Peoria. It is the second largest Catholic high school in the Quad Cities.
Alleman Catholic High School was established in 1949 and named for Rev John George Alleman. Its first principal was Father John F. O'Connor.
Alleman Catholic High School competes in the Illinois High School Association and is a member school of the Western Big 6 Conference. Available for the male students are baseball, basketball, cross country, football, golf, soccer, tennis, track & field, and wrestling. Female students have cheerleading, basketball, cross country, the Emeralds dance team, soccer, softball, tennis, track & field, golf, and volleyball available. The school's mascot is the Pioneer.