Clevan "Tank" Williams (born June 30, 1980) is an American former professional football player who was a safety in the National Football League (NFL). He played college football for the Stanford Cardinal and was selected by the Tennessee Titans in the second round of the 2002 NFL draft. He also played for the Minnesota Vikings and New England Patriots. Williams is currently a fantasy football analyst at Yahoo! Sports and a real-estate agent in the San Francisco area.

Williams attended Bay High School in Bay St. Louis, Mississippi where he played football as a safety as well as a quarterback. He also played basketball and ran track all four years in high school. During high school, he was also employed by the Winn-Dixie grocery store in Bay St. Louis where he worked as a bag boy.

According to Williams, his nickname came from his sister: as an infant, he drank so much milk that his sister suggested to his mother that his mother should give him a tank of milk instead of a bottle.^[1]

Williams attended Stanford University, where he played in 10 games as a true freshman in 1998. He started six games at free safety in 1999, and earned second-team All-Pacific-10 Conference honors as a junior. In his senior season, Williams was a first-team All-Pac-10 pick, becoming the first defensive back in school history to win national first-team honors.