Hannigan is a surname. Among the people with this name are:
- Alyson Hannigan, an American actress
- Barbara Hannigan, a Canadian soprano
- Ed Hannigan, an American comic book writer and artist
- James Hannigan, a British composer
- Lisa Hannigan, an Irish singer and songwriter
- Miss Agatha Hannigan, fictional character in Annie
- Robert Hannigan, a senior British civil servant and author of a report informally known as the Hannigan Report