George Segal was originally cast in the lead role but walked off the set shortly after filming began.
The song being played while Dudley Moore and Bo Derek are making love is Ravel's "Bolero". Bo Derek later starred in a movie called Bolero (1984).
Peter Sellers turned down numerous offers to play the lead role, but made a cameo appearance as a jazz drummer in a restaurant scene. The scene was cut from the movie.
Although this movie's title was widely understood to say that Bo Derek's looks rated 10 out of 10, the rating actually given to her character's looks in the scene where the subject arises is 11 out of 10.
Blake Edwards was inspired to write this script when he caught a brief glimpse of a woman on the way to her wedding.
The license plate of George Webber's yellow Rolls Royce convertible is "ASCAP", which stands for "American Society of Composers, Authors and Publishers"
Entirely thanks to this movie, Ravel's "Bolero" is, to this day, one of the most expensive songs for which to obtain usage rights for film and TV (in excess of $25,000) and, according to SACEM (the French equivalent of ASCAP), Ravel's estate earns more royalties than any other French composer.