Philadelphia built as much as a 30-point lead early in the fourth quarter while improving its home record this season to 9-2. The 76ers have the only winning record in the Atlantic Division.
Williams scored 17 points, Jrue Holliday added 15 and Jodie Meeks had 14. The 76ers limited Charlotte to 10 first-quarter points and owned a 59-37 halftime lead.
Kemba Walker had 14 for the Bobcats, who were outrebounded by 12 and shot a mere 38 percent from the floor.
Charlotte went into the night's action tied for the fewest wins in the NBA with three. The Bobcats' current losing streak has reached seven games.