Mary Hayward Weir
- Category : 1915-births
- Type : PSP
- Profile : 5/1 - Heretical / Investigator
- Definition : Split - Small (57)
- Incarnation Cross : LAX Prevention 2
American steel heiress and socialite, the wealthy widow of Pittsburgh steel king Ernest T. Weir, and the former wife of Polish author Jerzy Kosiński.
On 2 June 1958 in Weirton, West Virginia, a public library called "The Mary H. Weir Public Library" was named in her honour with Weir cutting the ribbon in person.
In 1965, Kosiński dedicated his novel The Painted Bird to her, and it was at this time that she began to feel ill. Kosinski fictionalized his marriage to Mary Hayward Weir in his 1977 novel Blind Date referring to her under the pseudonym Mary–Jane Kirkland.
Mary Hayward Weir was diagnosed with a brain tumour, of which she died on 1 August 1968, aged 52.