John McCormack may refer to:
John McCormack (tenor) (1884–1945), Irish tenor
John Brendan McCormack (born 1935), Catholic bishop of the Diocese of Manchester, New Hampshire
John William McCormack (1891–1980), politician from Massachusetts, Speaker of the House of Representatives, 1962–1971
John McCormack (Ohio politician) (born 1940s), former member of the Ohio House of Representatives
John McCormack (boxer) (1935–2014), Scottish boxer
Young McCormack (born 1944), Irish boxer born John McCormack
John McCormack (baseball), American college baseball coach
John McCormack (Irish footballer) (fl. 1970s–1980s), Irish soccer player
John McCormack (footballer, born 1955), Scottish football player and manager
John McCormack (footballer, born 1965), Scottish football player
John McCormack (ice hockey) (1925–2017), Canadian ice hockey player
John McCormack (racing driver), Australian racer
John Edward McCormack (1917–1953), lawyer and political figure in Saskatchewan
John MacCormac, Irish timber merchant
Cec McCormack (John Cecil McCormack, 1922–1995), English footballer