Hayley Nichole Williams (born December 27, 1988) is an American singer and songwriter. She is the lead vocalist and only constant member of the rock band Paramore, which she co-founded in 2004.

Williams was born and raised in Meridian, Mississippi. Her parents divorced when she was 13 and she moved with her mother to Franklin, Tennessee, where she later formed Paramore alongside Josh Farro, Zac Farro, and Jeremy Davis. Paramore has released six studio albums: All We Know Is Falling (2005), Riot! (2007), Brand New Eyes (2009), Paramore (2013), After Laughter (2017), and This Is Why (2023). It has featured a continuously changing line-up (currently consisting of Williams, Zac Farro, and Taylor York) with Williams being the only member to appear on all six albums.

Williams' non-Paramore musical work includes the song "Teenagers" for the soundtrack of the film Jennifer's Body (2009) and collaborations with The Chariot, October Fall, New Found Glory, Set Your Goals, and Zedd. In 2010, she was featured on the single "Airplanes" by B.o.B, which peaked at No. 2 on the U.S. Billboard Hot 100. The sequel to the song, "Airplanes, Part II", featured new verses from B.o.B. and a guest verse from Eminem with Williams' vocals remaining. This gained a nomination for the Grammy Award for Best Pop Collaboration with Vocals. In 2023, she featured on Taylor Swift's re-recording of her 2010 album Speak Now on the track "Castles Crumbling". She has also released the solo EPs Petals for Armor I (2020) and Petals for Armor II (2020), the subsequent full-length solo album Petals for Armor (2020), and her second solo album Flowers for Vases / Descansos (2021).

Williams' other ventures include the music series Kiss-Off and the hair dye company Good Dye Young.