| Leyla Yeniay Köseoğlu | |
| Parliament1: | 17th |
| Term Start1: | 6 November 1983 |
| Term End1: | 29 November 1987 |
| Parliament2: | 18th |
| Term Start2: | 29 November 1987 |
| Term End2: | 20 October 1991 |
| Parliament3: | 19th |
| Term Start3: | 6 November 1991 |
| Term End3: | 24 December 1995 |
| Birth Name: | Leyla Yeniay |
| Birth Date: | 1926 |
| Birth Place: | Beşiktaş, Istanbul, Turkey |
| Death Place: | Bodrum, Muğla, Turkey |
| Nationality: | Turkish |
| Party: | Motherland Party ANAP |
| Children: | 2 |
| Occupation: | Politician |
| Mawards: | is not set --> |
Leyla Yeniay Köseoğlu (1926 – 19 May 2002) was a Turkish politician. She served three terms in the parliament.
She co-founded Motherland Party (Turkish: Anavatan Partisi, ANAP) in 1983, when political parties were allowed after the junta of the 1980 coup d'état banned all parties.
She ran for the Deputy of Istanbul in the 1983 general election, and entered the Grand National Assembly of Turkey. She served in the 17th Parliament until 1987. She continued her political career in the 1987 general election and served in the 18th Parliament. In 1991, she took part at the general election and served the last time in the parliament until 1995.
Leyla Yeniay was born to Abdi Yeniay and Afife in Beşiktaş district of Istanbul, Turkey in 1926. Her grandfather Hacı Bekir Efendi, originated from AKşekir, was the Deputy of Konya in the first and second term of the First Parliament in the 1920s. She completed her education at Arnavutkoey American High School for Girls in Istanbul.
She worked as a merchant and exporter.
She gave birth to two sons, AHmet and Mustafa Köseoğlu.
In 1999, she was sentenced to one year, three months imprisonment and 4.5 million Turkish lira (around 9 US$) fine for breaking the Forest Law by cutting down trees as the chair of a house building cooperative. The imprisonment was postponed.
LeylaYeniay Köseoğlu died from heart attack in Bodrum, Muğla on 19 May 2002. Her body was transferred to Istanbul and was buried in the family grave at Edirnekapı Martyr's Cemetery following the religious service held at Şişli Mosque two days later.