Diane Eve Warren (born September 7, 1956) is an American songwriter. She has won an Academy Honorary Award, Grammy Award, an Emmy Award, two Golden Globe Awards, and, three consecutive Billboard Music Awards for Songwriter of the Year.

Warren's career was jump-started in 1985 with "Rhythm of the Night" by DeBarge. In the late 1980s, she joined forces with the UK music company EMI, where she became the first songwriter in the history of Billboard magazine to have seven hits, all by different artists, on the singles chart at the same time, prompting EMI's UK Chairman Peter Reichardt to call her "the most important songwriter in the world". She has been rated the third most successful female artist in the UK.

Warren has written nine number-one songs and 32 top-10songs on the Billboard Hot 100 including "If I Could Turn Back Time" (Cher, 1989), "Because You Loved Me" (Celine Dion, 1996), "How Do I Live" (LeAnn Rimes, 1997), and "I Don't Want to Miss a Thing" (Aerosmith, 1998). Two of the top 13 hits in the Hot 100's 57-year history were composed by Warren. She has been inducted into the Songwriters Hall of Fame and received a star on the Hollywood Walk of Fame. Her UK success saw her win an Ivor Novello Award when she received the Special International Award in 2008. Warren has been nominated for 14 competitive Academy Award nominations without a win; she received an honorary Oscar at the Governors Awards in November 2022.