Trivia

Wilder directed Marilyn Monroe in The Seven Year Itch (1955) and Some Like It Hot (1959). He grew to despise her demands for star treatment and her poor work ethic, and thus included the party-girl Monroe-esque character in this film.

Billy Wilder also used the character name Sheldrake in Sunset Blvd. (1950), Ace in the Hole (1951), and Kiss Me, Stupid (1964).

Billy Wilder originally thought of the idea for the film after seeing Brief Encounter (1945) and wondering about the plight of a character unseen in that film. Shirley MacLaine was only given forty pages of the script because Wilder didn't want her to know how the story would turn out. She thought it was because the script wasn't finished.

Paul Douglas was cast as Sheldrake but died before filming began.

In 1968, playwright Neil Simon adapted the screenplay as the book for the Broadway musical "Promises, Promises". It spawned the hit song "I'll Never Fall in Love Again", composed by Burt Bacharach and Hal David.

Although Adolph Deutsch received sole screen credit for the music score, the very popular "Theme from The Apartment" was actually a pre-existing piece of music (originally "Jealous Lover", 1949) by British composer Charles Williams, who was known for his scores for British films and BBC radio dramas.

Shirley MacLaine filmed her famous cameo in Ocean's Eleven (1960) during a break in filming this movie.

According to Shirley MacLaine on her official web site, much of the movie was written as filming progressed. The gin rummy game was added because at the time she was learning how to play the game from her friends in the Rat Pack. Likewise, when she started philosophizing about love during a lunch break one day, this was also added to the script.

The name on the door next to Baxter's office is T.W.Plews. Tom Plews was the prop master.

The office Christmas party scene was actually filmed on December 23, 1959, so as to catch everybody in the proper holiday mood. Billy Wilder filmed almost all of it on the first take, stating to an observer, "I wish it were always this easy. Today, I can just shout 'action' and stand back."

This is the first Best Picture Oscar winner to specifically refer to a previous winner, in this case Grand Hotel (1932), which Baxter attempts to watch on television but is too long delayed because of commercials. Bud's boss also refers to Bud and Fran having "a lost weekend" together in Bud's apartment, a reference to Billy Wilder's earlier Oscar winner, The Lost Weekend (1945).

This was the last Black and White movie to win Best Picture at The Academy Awards until Schindler's List (1993).

The "C.C." in C.C. Baxter is short for Calvin Clifford

Premiere voted this movie as one of "The 50 Greatest Comedies Of All Time" in 2006.

In 2007, the American Film Institute ranked this as the #80 Greatest Movie of All Time.

The wool coat Fran wears in various scenes actually belonged to Audrey Young, the wife of Billy Wilder).

It was said that while filming the scene where C.C. Baxter sleeps in Central Park in the rain, Billy Wilder had to spray Jack Lemmon with anti-freeze to keep him from freezing.

To get Fran (Shirley MacLaine) to look genuinely startled when her brother-in-law punches Calvin (Jack Lemmon), director Billy Wilder smacked together two pieces of 2x4 during the shoot.

The nasal spray used by Jack Lemmon was actually milk. Real nasal spray would not have shown up on camera.

Billy Wilder claimed that he and I.A.L. Diamond already had Jack Lemmon in mind to play Baxter when they wrote the screenplay. In an interview years later, Lemmon confirmed this.