"No Sé Olvidar" ("I Don't Know How to Forget") is a song written by Kike Santander and performed by Mexican recording artist Alejandro Fernández.

It was co-produced by Santander and Emilio Estefan and was released as the third single from Me Estoy Enamorando by Sony Music Mexico in 1997.

A music video was made for the track which features Fernández hopelessly attempting to not remember his lover only to slowly delve into insanity.

It reached the top of the Billboard Hot Latin Songs chart in the United States and spent eight weeks at this position.

"If I had released another album of just rancheras, people would have just expected the same thing, and then they would have begun to judge me by that one [musical] theme", Fernández explained.

[10][11] In the United States, "No Sé Olvidar" debuted at number 28 on the Billboard Hot Latin Songs chart on the week of 21 February 1998.

[16] Eliseo Cardona of El Nuevo Herald highlighted "No Sé Olvidar" as one of the boleros where Fernández performs with "intensity and passion".

Fernández lost the first award to "Por Mujeres Como Tu" by Pepe Aguilar and the second to "Vuelve" by Ricky Martin.

[20] It received a nomination for Video of the Year at the 10th Annual Lo Nuestro Awards in 1998,[21] but lost to "Ella y Él" by Ricardo Arjona.