1991 Westchester Cup

The 1991 Westchester Cup was a women's tennis tournament played on outdoor hard courts at the Manhattanville College in Westchester, New York in the United States. It was the 9th and final edition of the event played in the state of New York since 1968 where it originated as the Madison Square Garden Challenge Trophy, the second played in Westchester, and was part of the Tier V series of the 1991 WTA Tour. The tournament was played from July 22 through July 28, 1991. Unseeded Isabelle Demongeot won the singles title and earned $18,000 first-prize money.

Isabelle Demongeot defeated Lori McNeil 6–4, 6–4

• It was Demongeot's only singles title of her career.

Rosalyn Fairbank / Lise Gregory defeated Katrina Adams / Lori McNeil 7–5, 6–4

• ITF tournament edition draws
• WTA tournament draws