| Nilay Esen Ersun | |
| Birth Date: | 3 January 1987 |
| Birth Place: | Antakya, Hatay Province, Turkey |
| Sport: | Athletics |
| Event: | Long-distance, marathon |
| Club: | Bursa Büyülşehir Belediye SK |
Nilay Esen Ersun (born January 3, 1987) is a Turkish female long-distance runner specialized in marathon. She is a member of Bursa Büyülşehir Belediye SK.
In 2005, she received a two-year ban from the track due to positive testing for illegal substance Metenolone.
She took part at the 2015 Hamburg Marathon in Germany, and finished in 2:37:09, meeting the qualifying time standard for Olympics. So, she earned a quota spot for women's marathon in the 2016 Summer Olympics.