Christina María Aguilera ( AG-il-AIR-ə, Spanish: [kɾisˈtina maˈɾi.a aɣiˈleɾa]; born December 18, 1980) is an American singer, songwriter, actress, and television personality. An influential figure in music, Aguilera is noted for her four-octave vocal range, melismatic singing style, use of the whistle register, and continual reinvention of her image and sound. Referred to as the "Voice of a Generation", she was ranked among the greatest singers of all time by Rolling Stone. Her works have incorporated socially conscious and sexual themes, generating both controversy and critical acclaim.

After appearing on The All New Mickey Mouse Club (1993–1994), Aguilera recorded the theme song, "Reflection", for the animated film Mulan (1998) and signed a record deal with RCA Records. She rose to fame as a teen idol with her self-titled debut album (1999), which topped the US Billboard 200 and garnered three US Billboard Hot 100 number-one singles: "Genie in a Bottle", "What a Girl Wants" and "Come on Over Baby (All I Want Is You)". Aguilera took on a more provocative image on Stripped (2002), one of the best-selling albums of the 21st century. After another retro-inspired reinvention, she scored her second US number-one album, Back to Basics (2006). Throughout these periods, she amassed worldwide hits, such as "Lady Marmalade", "Dirrty", "Beautiful" and "Ain't No Other Man".

During the early 2010s, Aguilera featured on the worldwide top ten singles "Moves like Jagger", "Feel This Moment" and "Say Something"; the first of these topped the Hot 100, making her the fourth woman in history to top the chart over three consecutive decades. She also starred in the film Burlesque (2010) and contributed to its soundtrack, earning a Golden Globe Award nomination. Aguilera remained musically active, having released a total of nine studio albums. Her other ventures included a role in the television series Nashville (2015); roles in the films The Emoji Movie (2017) and Zoe (2018); becoming an ambassador for the World Food Programme (WFP); co-founding the company Playground; and serving as a coach on the reality competition show The Voice (2011–2016).

Aguilera is one of the best-selling music artists of all time, with over 100 million records sold worldwide. She has been regarded as one of the most influential Latin artists in the United States, having helped shape the "Latin explosion" in the early 2000s with Mi Reflejo (2000), the best-selling Latin pop album of that year. Time named her one of the 100 most influential people in the world in 2013. Aguilera's accolades include five Grammy Awards, two Latin Grammy Awards, two MTV Video Music Awards, a Juno Award, a Billboard Music Award, three Billboard Latin Music Awards, and a star on the Hollywood Walk of Fame. She was also named a Disney Legend, in recognition of her contributions to the Walt Disney Company.