"Mistletoe" is a song by Canadian singer Justin Bieber. It was written and produced by Nasri, and Adam Messinger. The song was released on October 17, 2011 as the lead single from his second studio album, Under the Mistletoe (2011). "Mistletoe" is a Christmas song with elements of pop and R&B genres, while making use of reggae influences.

"Mistletoe" received generally positive reviews from most music critics. The song reached the top ten in Canada, Denmark and Norway, while also reaching the top forty in ten other countries. The song's accompanying music video was directed by Roman White. It features the singer singing on a snowy, lit-up street, resembling the Christmas holiday season.

Bieber first premiered the song live on the My World Tour on October 6, 2011 at Olympic Stadium in Rio de Janeiro, Brazil. During the performance, Bieber confirmed that the song would be released on iTunes worldwide on October 17, 2011. In an interview with MTV News, Bieber said, "I'm really excited. [The song is] really catchy. I know all my fans are going to love it. It's something that I feel like they're going to be singing every Christmas."

Justin Drew Bieber ( /ˈbiːbər/ BEE-bər, born March 1, 1994) is a Canadian Pop/R&B singer-songwriter, musician, and actor. Bieber was discovered in 2008 by Scooter Braun, who came across Bieber's videos on YouTube and later became his manager. Braun arranged for him to meet with Usher in Atlanta, Georgia, and Bieber was soon signed to Raymond Braun Media Group (RBMG), a joint venture between Braun and Usher, and then to a recording contract with Island Records offered by L.A. Reid. Bieber's debut single, "One Time", was released in 2009 and peaked in the top twenty in Canada and charted in the top thirty in several international markets. His debut album, the seven-track EP My World, followed in November 2009, and was soon certified platinum in the United States. He became the first artist to have seven songs from a debut album chart on the Billboard Hot 100.