Mary Eaton (January 29, 1901 – October 10, 1948) was an American stage actress, singer, and dancer in the 1910s and 1920s, probably best known today from her appearance in the first Marx Brothers film, The Cocoanuts (1929).

Eaton, a native of Norfolk, Virginia, began attending dance lessons in Washington, DC, along with her sisters Doris and Pearl, at the age of seven.

After The Blue Bird ended, in 1912, the three Eaton sisters and their younger brother Joe began appearing in various plays and melodramas for the Poli stock company.

Glorifying the American Girl (1929) was to be a spectacular, all-talking extravaganza worthy of Ziegfeld (who receives screen credit), with musical pageants filmed in Technicolor.

Paramount gave Eaton the starring role of an ambitious shopgirl who goes into show business and fights her way to the top, with little regard for her friends and colleagues.

Eaton's singing and dancing routines, including her signature pirouette sequence, were featured, but they couldn't overcome her limited screen personality.

The film was completed in June 1929 but Paramount executives considered it too weak to release, and shot new footage of celebrities Eddie Cantor.

After a terrible preview, Paramount actually sneaked the film out in late 1929 to smaller towns,[6] hoping to attract curious audiences with Broadway luster, and avoiding a New York premiere until early 1930.