"You Will Know" is a song written and recorded by American R&B singer-songwriter Stevie Wonder, taken from his 1987 Characters album. It is the opening track on the album, and is the second single from the album as well. This is Stevie Wonder's 20th and final number-one R&B hit single. Wonder performed the song along with R&B quartet Jodeci and Mary J. Blige on an episode of The Arsenio Hall Show in late 1992.