"Blue World" is a song by American rapper Mac Miller from his sixth studio album, Circles (2020). It was sent to rhythmic contemporary radio on February 4, 2020, as the second single from the album. The song was written by Miller and Guy Lawrence of Disclosure, with George Forrest and Robert Wright receiving writing credits due to a use of "It's a Blue World" by the Four Freshmen as a sample. The song was produced by Lawrence and Jon Brion.
The song was ranked number 71 on The Fader<nowiki/>'s list of the 100 best songs of 2020. It was also on former U.S. president Barack Obama's playlist of his favorite music of 2020, and would go on to be featured in the soundtrack for MLB The Show 23.
Heran Mamo of Billboard called "Blue World" an "electronic-tinged rap" song. The track contains a sample of "It's a Blue World" by American vocal quartet The Four Freshmen, as well as a "syncopated drum pattern and hip-hop rhymes".