The music of Deltarune comprises multiple soundtrack albums created and scored by Toby Fox, featuring guest appearances by Laura Shigihara, Lena Raine, Marcy Nabors, Itoki Hana, and Alex Rosetti. The soundtrack album for Chapter 1 was released on Bandcamp on November 1, 2018, a day after the game was launched. In collaboration with Fangamer, Fox released the first chapter's soundtrack on vinyl in 2019. On September 17, 2021, the second soundtrack album was released for Chapter 2 the same day as the game was launched. On June 5, 2025, the third soundtrack album was released for Chapters 3 and 4 the same day as the game was launched.

Deltarune Chapter 1 (Original Game Soundtrack), also known as Deltarune Chapter 1 OST, comprises the music featured in the first chapter of the game.

All tracks are written by Toby Fox.

Deltarune Chapter 2 (Original Game Soundtrack), also known as Deltarune Chapter 2 OST, comprises the music featured in the second chapter of the game.

Lena Raine and Marcy Nabors provided additional transcription and arrangement assistance.

All tracks are written by Toby Fox.

Deltarune Chapters 3+4 (Original Game Soundtrack), also known as Deltarune Chapters 3+4 OST, comprises the music featured in the third and fourth chapters of the game titled.

Alex Rosetti, Lena Raine, and Itoki Hana are credited as contributors for some tracks. Otherwise, all tracks are written by Toby Fox.