John McGowan may refer to:

• John McGowan (Medal of Honor) (1831–?), American Civil War sailor and Medal of Honor recipient
• John McGowan (naval officer) (1843–1915), American Civil War veteran and US Navy rear admiral
• John McGowan (politician) (1845–1922), Ontario MPP and member of the Canadian House of Commons
• John Reid McGowan (1872–1912), Australian boxing champion
• J. P. McGowan (1880–1952), American Hollywood actor and director
• Jack McGowan (1894–1977), American Broadway writer, performer and producer
• Jack McGowan (golfer) (1930–2001), American professional golfer
• John McGowan (footballer) (born 1952), Scottish footballer
• John McGowan (professor) (born 1953), American academic, Distinguished Professor of the Humanities at the University of North Carolina
• John W. McGowan, member of the New York State Assembly