Cosette Saint-Omer-Roy (last name also spelled St. Omer-Roy, born 6 March 1902, deceased 14 September 1985[1]) was a French tennis player.

With Alice Weiwers as her partner, she won the doubles' event at the Tournoi de France, a stand-in tournament in place of the French Championships three times during World War II.

[2] With Weiwers, she also reached the semifinals before the war at the 1939 French Championships, where they lost to the eventual champions Jadwiga Jędrzejowska and Simonne Mathieu.

In singles, Saint-Omer-Roy entered the French Championships twice in 1938 and 1939, but did not win a match either time.

Saint-Omer-Roy also served as manager of the Cannes Tennis Club from 1932.