"Lo Malo" (previously known as "Chico Malo")[1][2] is a song by Spanish singers Aitana and Ana Guerra, originally written in English language under the title "Boy No Good" by Tye Morgan and Will Simms and adapted into Spanish language by Brisa Fenoy.

[11] On 4 December 2017, the Spanish broadcaster Televisión Española (TVE) confirmed that they would use the successful music reality program Operación Triunfo to select their act for the Eurovision Song Contest 2018.

[12] It was later revealed on 20 December that the final five singers of the program's ninth series would perform in "Gala Eurovisión", which would be where the Spanish public would choose both the song and its performers for the Eurovision Song Contest.

[17][18][19] The Spanish branch of OGAE, the international fan club of the Eurovision Song Contest, selected “Lo Malo” to represent Spain in the visual event OGAE Second Chance Contest in 2018.

In April 2018, Inditex-owned brand Stradivarius released a T-shirt inspired by the song which was sold out in less than twenty four hours.