Written by Ricky Vela, "El Chico del Apartamento 512" is a cumbia song with influences of Colombian and South American music.

Lyrically, the song describes a female protagonist who knocks on her love interest's apartment door (number 512) and is heartbroken when his sister (who she initially mistakes for his girlfriend) answers it.

Justino Aguilar of Billboard magazine, called "El Chico del Apartamento 512" as one of Selena's "most memorable songs".

[1] Musicologist Howard Blumenthal called the song's production "perfect" in his book The World Music CD Listener's Guide (1998).

[1] Musicologists Ilan Stavans and Harold Augenbraum called the song "brassy" and noticed how the lyrics are constructed in story-song form.

[7] "El Chico del Apartamento 512" was later reworked and included on Selena's posthumously released remix/duet album Enamorada de Ti (2012).

[14] American singer Kris Melody and Mexican group Los Tigrillos recorded the song for the tribute album Mexico Recuerda a Selena (2005).

[15] Mexican singer Graciela Beltrán performed and recorded "El Chico del Apartamento 512" for the live televised tribute concert Selena ¡VIVE!