John Callahan
John Callahan may refer to:
- John Callahan (actor), American actor; best known from the soap opera All My Children
- John Callahan (cartoonist), cartoonist
- John Callahan (Wisconsin politician), Wisconsin Superintendent of Public Instruction
- John B. Callahan, mayor of Bethlehem, Pennsylvania and Democratic nominee for the U.S. House of Representatives
- John F. Callahan, writer and editor of numerous volumes related to African-American literature
- John H. Callahan, American Civil War soldier and Medal of Honor recipient
- John M. Callahan, chairman of the Democratic Party of Wisconsin
- John Ross Callahan, American dentist
- John Callahan (catcher), American baseball player
- John Callahan (pitcher), baseball player
- John Callahan (skier), American Olympic skier
- John Callahan (wrestler), American professional wrestler
- John Callahan (outlaw), American outlaw and bank robber