Otherwise Engaged is a bleakly comic play by English playwright Simon Gray. The play previewed at the Oxford Playhouse and the Richmond Theatre, and then opened at the Queen's Theatre in London on 10 July 1975, with Alan Bates as the star and Harold Pinter as director, produced by Michael Codron. Ian Charleson co-starred as Dave, a Glasgow lout. Michael Gambon took over from Bates in 1976, "playing it for a year, eight times a week." The play also had a successful run on Broadway, opening in February 1977 with Tom Courtenay as Simon and Carolyn Lagerfelt as Beth. It won the New York Drama Critics' Circle Award for Best Play.

Simon James Holliday Gray was an English playwright and memoirist who also had a career as a university lecturer in English literature at Queen Mary, University of London, for 20 years. While teaching at Queen Mary, Gray began his writing career as a novelist in 1963 and, during the next 45 years, in addition to five published novels, wrote 40 original stage plays, screenplays, and screen adaptations of his own and others' works for stage, film and television and became well known for the self-deprecating wit characteristic of several volumes of memoirs or diaries.