John Costello
John Costello may refer to:
- John Costello , American baseball pitcher
- John Costello , English footballer
- John Costello , British military historian
- John A. Costello, Taoiseach of Ireland
- John M. Costello, U.S. Representative from California
- John Costello , U.S. Navy sailor and Medal of Honor recipient
- John Costello , Australian pastoralist
- John W. Costello, American attorney and politician in Massachusetts
- John Costello, Gaelic football player from County Laois
- John P. Costello, U.S. Army general