[9] "Megalovania", the song used during the boss battle against Sans, had previously been used within Homestuck and in one of Toby Fox's EarthBound ROM hacks.

[17] Another album of jazz duets based on Undertale's songs, Prescription for Sleep, was performed and released in 2016 by saxophonist Norihiko Hibino and pianist Ayaki Sato.

A Mii Fighter costume based on Sans was made available for download in the crossover title Super Smash Bros.

[10] Oxford notes this track in particular demonstrates Fox's ability at "turning old songs into completely new experiences", used throughout the game's soundtrack.

As part of the fifth anniversary of the game, Fox streamed footage with permission of a 2019 concert of the Undertale songs performed by Music Engine, an orchestra group in Japan, with support of Fangamer and 8–4.

[28] The track "Megalovania" has seen extensive use in Internet memes[29] and was already popular among the Homestuck fandom, as another version of the song was associated with the characters Vriska Serket, Jack Noir, and Aradia Megido.