Lya Isabel Fernández Olivares (born 24 July 2007) is an inactive Mexican tennis player.

She reached a best singles ranking of world No.

[1] On the ITF Circuit, she has won one title in singles.

In 2022, Fernández Olivares won her first title in singles in Cancún, Mexico.

[2] Fernández Olivares made her WTA Tour singles debut at the 2023 Guadalajara Open where she entered the main draw as a wildcard player, losing in the first round to Hailey Baptiste.