First-seeded Helen Wills Moody defeated Eileen Bennett Whittingstall 6–4, 6–1 in the final to win the women's singles tennis title at the 1931 U.S. National Championships.

[1] Wills Moody won the tournament without losing a set.

[2][3][4] The tournament used two lists of eight players for seeding the women's singles event; one for U.S. players and one for foreign players.

Helen Wills Moody is the champion; others show in brackets the round in which they were eliminated.

[5][6]