Colgan is an Irish surname, an Anglicized form of Irish Ó Colgáin meaning "descendant of Colga", a personal name based on colg "thorn," "sword." Notable people with the surname include:
Charles J. Colgan (1926-2017), American Democratic politician and businessman from Virginia
Eileen Colgan (c. 1934 – 2014), Irish actress
Flavia Colgan, American Democratic strategist
Gerry Colgan (1951–2011), Scottish teacher and footballer
Jay Colgan, American Businessman
Jenny Colgan, British novelist
John Colgan, Irish hagiographer and historian
Michael Colgan (disambiguation), multiple people
Nick Colgan, Irish football goalkeeper
Stevyn Colgan, Cornish writer, artist and songwriter
