Act One most often refers to the first act of a play, opera, or other dramatic performance.
Act One, Act I, ACTI and similar may also refer to:
Theatre, film and books Act One (book), a 1959 memoir by Moss Hart Act One (1963 film), a film version of the memoir Act One (play), a 2014 theatrical adaptation of the memoir by James Lapine Act One, Inc., an organization for aspiring filmmakers Act One (2026 film), an upcoming American psychological thriller film
Music "Act I: Eternal Sunshine (The Pledge)", a 2007 composition by Jay Electronica Act I and II, a 1993 concert tour by Prince Act One (album), a 1970 album by Beggars Opera Act One, an album by Marian Hill Act One, a 2006 EP by I Hate Kate Act I (Seldom Scene album), a 1972 album by the Seldom Scene Act I: Live in Rosario, a 2012 live album by Tarja Turunen Act I: The Lake South, the River North a 2006 album by the Dear Hunter Act I: Renaissance, or simply Renaissance, a 2022 album by Beyoncé Act 1 (The Pilgrim), a 2022 album by Tapir! Act. 1 The Little Mermaid, 2016 EP by Gugudan
See also The Act One Group, company founded by Janice Bryant Howroyd Acton Trussell (UK), formerly, Actone (England) ACTI (Automated Computer Telephone Interviewing) Act 1 adaptor protein