The 1931 French Championships (now known as the French Open) was a tennis tournament that took place on the outdoor clay courts at the Stade Roland-Garros in Paris, France. The tournament ran from 22 May until 31 May. It was the 36th staging of the French Championships and the second Grand Slam tournament of the year. Jean Borotra and Cilly Aussem won the singles titles.
See main article: 1931 French Championships – Men's singles. 
Jean Borotra defeated Christian Boussus 2–6, 6–4, 7–5, 6–4
See main article: 1931 French Championships – Women's singles. Cilly Aussem defeated 
Betty Nuthall 8–6, 6–1
George Lott / John Van Ryn defeated Vernon Kirby / Norman Farquharson 6–4, 6–3, 6–4
Eileen Bennett Whittingstall / Betty Nuthall defeated 
Cilly Aussem / Elizabeth Ryan 9–7, 6–2
Betty Nuthall / Patrick Spence defeated Dorothy Shepherd Barron / Bunny Austin 6–3, 5–7, 6–3