Gwen Renée Stefani (; born October 3, 1969) is an American singer, songwriter, and fashion designer. She is a co-founder and the lead vocalist of the band No Doubt that experienced major success after their breakthrough studio album Tragic Kingdom (1995) along with various successful singles, including "Just a Girl", "Don't Speak", "Hey Baby", and "It's My Life". During the band's hiatus, Stefani embarked on a solo pop career in 2004 by releasing her debut studio album Love. Angel. Music. Baby. Inspired by pop music from the 1980s, the album was met with both critical and commercial success. It spawned three commercially successful singles: "What You Waiting For?", "Rich Girl", and "Hollaback Girl". The latter reached number one on the Billboard Hot 100 chart while also becoming the first US download to sell one million copies. In 2006, Stefani released her second studio album The Sweet Escape. The album produced two successful singles: "Wind It Up" and the album's title track "The Sweet Escape". Her third solo album, This Is What the Truth Feels Like (2016), became her first solo album to reach number one on the Billboard 200 chart.

Stefani has won three Grammy Awards. As a solo artist she has received various accolades, including an American Music Award, Brit Award, World Music Award and two Billboard Music Awards. In 2003, she debuted her clothing line L.A.M.B. and expanded her collection with the 2005 Harajuku Lovers line, inspired by Japanese culture and fashion. During this time Stefani performed and made public appearances with four back-up dancers known as the Harajuku Girls. She was married to British musician Gavin Rossdale from 2002 to 2016 and they have three sons. Billboard magazine ranked Stefani the 54th most successful artist and 37th most successful Hot 100 artist of the 2000–09 decade. VH1 ranked her 13th on their "100 Greatest Women in Music" list in 2012. Including her work with No Doubt, Stefani has sold more than 30 million albums worldwide.