Charles Prosek Williams (October 11, 1947 – January 27, 2015) was a Major League Baseball pitcher, best known for being the player the New York Mets traded to the San Francisco Giants for Willie Mays in 1972.

On April 23, he made his major league debut at Wrigley Field in Chicago, pitching 2.2 innings and giving up four runs (two earned) in the Mets' 7–6 extra innings victory over the Cubs (the winning pitcher of the game was future Hall of Famer Nolan Ryan).

For the season, Williams compiled a 5–6 record, making nine starts, with a 4.78 earned run average and 53 strikeouts.

Following the conclusion of his baseball career, Williams was briefly a New York City taxi driver.

He later settled in Port Orange, Florida and died in Daytona Beach on January 27, 2015, from complications resulting from heart surgery.