Billboard 21 Under 21

21 Under 21 is an annual ranking by American music magazine Billboard beginning in [|2010]. It honours young musicians under the age of 21 in the music for impact over the previous and their potential to "rule pop culture zeitgeist over the next 12 months".
Taylor Swift topped the first ranking in 2010 at age 20. Justin Bieber, Lorde and Billie Eilish are the youngest acts to be #1. Willow Smith is the youngest act to appear on any ranking,. Smith also has the longest period of inclusion, appearing on five rankings across 11 years. Bieber; Camila Cabello; Eilish; Shawn Mendes; Lorde; Cody Simpson; Smith; Grace VanderWaal; The Linda Lindas and The Kid Laroi are tied for the most appearances, with five each. Bieber, Mendes and Ángela Aguilar are the only acts to top the ranking more than once. and

Poll results by year

;2 wins

;4 placements

;3 placements

;2 placements