Esther Szekeres née Klein (1910 - 2005) Hungarian mathematician, best known for the happy ending problem she pondered with Paul Erdős and which led to her marriage to the mathematician George Szekeres.

During World War II, Szekeres and her husband moved to Australia. In Sydney, she lectured at Macquarie University and lobbied to improve mathematics education in high schools in Australia and New Zealand.

As she collaborated with Erdős, Janice L. Malouf and John Selfridge on the paper Subsets of an interval whose product is a power, she has Erdős number 1.