Inspired by the real-life story of husband-and-wife lawyers William Dwight Whitney and Dorothy Whitney, who represented Raymond Massey and his ex-wife Adrianne Allen in their divorce. After the Massey divorce was over, the Whitneys divorced each other and married the respective Masseys.
In the scene in which Amanda is driving Adam to work, he tells her, "Oh, you're giving me the Bryn Mawr accent". Bryn Mawr College was Katharine Hepburn's alma mater, where she claimed to have gained her distinctive voice.
In her early monologue scene with Katharine Hepburn, Judy Holliday can be seen trembling. This was not acting, but nervousness. The inexperienced Holliday was terrified of performing with Hepburn.
Katharine Hepburn reportedly urged director George Cukor to focus the camera on Judy Holliday during a number of their shared scenes, not only because she was a fan of the new-to-movies Holliday but because it was hoped the studios would see how terrific Holliday was and cast her as the lead in Born Yesterday (1950), the role she'd created on Broadway. It worked.
The script called for Kip Lurie to write a song about his devotion to Amanda. Garson Kanin wrote a song for the moment, but nobody liked it. When he dared Katharine Hepburn to find a better song, she asked Cole Porter to do it. At the time, the leading lady's name was "Madeleine." Porter turned Hepburn down, saying it was impossible to do a song about a woman with that name. Then he suggested changing her name to Amanda. Eight days later, he presented them with a new song, "Farewell, Amanda." It was actually a re-working of "So Long, Samoa," a song he had written in 1940 and never used. Rather than charge MGM for his services, he asked that they make a large donation to the Red Cross.