Floor Jansen (pronounced ; born 21 February 1981 in Goirle) is a Dutch singer, songwriter, and vocal coach. She is the lead vocalist of Finnish symphonic metal band Nightwish.
Jansen first became known as a member of symphonic metal band After Forever, standing as their lead vocalist from 1997, when she joined at age 15, to their disbanding in 2009. When After Forever disbanded, she formed ReVamp and has released two albums with them. In 2012 following the departure of their lead vocalist Anette Olzon, Nightwish brought in Jansen as a touring member until the end of their Imaginaerum World Tour. In 2013, they announced Jansen was then their full-time lead vocalist.
A frequent collaborator of Arjen Anthony Lucassen, she is a member of his progressive metal supergroup Star One, and sang in the Ayreon albums Universal Migrator Part 1: The Dream Sequencer, 01011001, and The Source. She also sang lead vocals in several songs of the MaYan album Quarterpast and in Avalon's Angels of the Apocalypse. She is the older sister of fellow singer Irene Jansen, who also worked with Ayreon.