Spring Dell Byington (October 17, 1886 – September 7, 1971) was an American actress. Her career included a seven-year run on radio and television as the star of December Bride. She was a Metro-Goldwyn-Mayer contract player who appeared in films from the 1930's to the 1960's. Byington received a nomination for an Academy Award for Best Supporting Actress for her role as Penelope Sycamore in You Can't Take It with You (1938).

Personal life Byington spoke some Spanish, which she learned during the time spent with her husband in Buenos Aires; and she studied Brazilian Portuguese in her later years. In July 1958, she confided to reporter Hazel Johnson that she had acquired a "small coffee plantation" in Brazil the month before and was learning Portuguese. "Miss Byington explained that she first listens to a 'conditioning record' before she goes to sleep. An hour later, her Portuguese lessons automatically begin feeding into her pillow by means of a small speaker."

Byington was fascinated by metaphysics and science fiction novels, including George Orwell's 1984. She surprised her co-stars in December Bride with her knowledge of the Earth's satellites and the constellations in the night sky, and read The Magazine of Fantasy & Science Fiction.

In August 1955, Byington began taking flying lessons in Glendale, California, but the studio made her stop because of insurance problems.

In January 1957, she testified in the trial of the Sica brothers as a character witness in behalf of DaLonne Cooper, who was a friend and the script supervisor for December Bride.