Diana Ernestine Ross (American English: ; UK: ; born March 26, 1944) is an American singer and actress. She was the lead singer of the vocal group the Supremes, who became Motown's most successful act during the 1960s and one of the world's best-selling girl groups of all time. They remain the best-charting female group in history, with a total of 12 number-one pop singles on the U.S. Billboard Hot 100.

Following her departure from the Supremes in 1970, Ross embarked on a successful solo career with the release of her eponymous debut solo album. Between 1972 and 1980, Ross recorded four top ten albums with her most successful studio release being the album Diana. In a fifteen-year span, Ross recorded twelve top ten singles with six – "Ain't No Mountain High Enough", "Touch Me in the Morning", "Theme from Mahogany (Do You Know Where You're Going To)", "Love Hangover", "Upside Down" and "Endless Love" – topping the Billboard Hot 100, making her the female solo act with the most number-one songs in the United States at the time. Ross achieved international success with later songs such as "I'm Coming Out", "Chain Reaction", "If We Hold on Together", and "When You Tell Me That You Love Me".

Ross has also achieved mainstream success and recognition as an actress. Her first role was her Golden Globe Award-winning and Academy Award-nominated portrayal of Billie Holiday in the film Lady Sings the Blues (1972), which made her the first African-American actress to receive an Academy Award nomination for a debut film performance. The film's soundtrack became her only solo album to reach number-one on the U.S. Billboard 200 chart. She also starred in two other feature films, Mahogany (1975) and The Wiz (1978), and later appeared in the television films Out of Darkness (1994), for which she was nominated for a Golden Globe Award, and Double Platinum (1999).

Ross has sold over 100 million records worldwide as a solo artist, making her one of the best-selling music artists of all time. Between 1964 and 1981, Ross sang on eighteen number one US singles. In 2021, Billboard ranked her the 30th greatest charting artist of all time on the Billboard Hot 100. Her hits as a Supreme and a solo artist combined put Ross among the top-five artists on the Billboard Hot 100 singles chart from 1955 to 2018. She has scored a top 75 U.K. hit single for a record 33 consecutive years (1964–1996). In 1988, Ross was inducted to the Rock and Roll Hall of Fame as a member of the Supremes, and is one of the rare performers to have two stars on the Hollywood Walk of Fame. She is the recipient of a Special Tony Award in 1977, the Kennedy Center Honors in 2007, the Grammy Lifetime Achievement Award in 2012 and 2023 (becoming the first woman to win the award twice, the latter as a member of the Supremes), and the Presidential Medal of Freedom in 2016.