Hannigan is a surname. A spelling variant is Hannegan. Notable people with the surname Hannigan include:Alyson Hannigan, American actress Barbara Hannigan, Canadian soprano Ed Hannigan, American comic book writer and artist James Hannigan, British composer Lisa Hannigan, Irish singer and songwriter Ray Hannigan (1927–2020), Canadian ice hockey player Robert Hannigan, senior British civil servant and author of a report informally known as the Hannigan Report Robyn E. Hannigan, American academic in the field of science Thomas M. Hannigan (1940–2018), American businessman and politicianFictional characters:Miss Agatha Hannigan, fictional character in Annie
