Jason Chandler Williams (born November 18, 1975) is an American professional basketball player who currently plays for the Orlando Magic. He started his NBA career in 1998, and retired after ten years in September 2008. He returned from retirement on August 19, 2009 and signed with the Orlando Magic.

Following his suspension by the University of Florida, Williams decided to make himself eligible for the NBA Draft. He was the seventh overall selection in the 1998 NBA Draft by the Sacramento Kings.

In his rookie year, the Kings, with a roster that included newcomers Williams, Chris Webber, Vlade Divac, and Peja Stojaković, turned into a playoff contender. That year, Williams' number 55 jersey was among the top five sellers of all NBA players.

On July 20, 2000, Williams was suspended for the first five games of the 2000–01 NBA season for failure to comply with his treatment obligations under the NBA's anti-drug program. The NBA does not release details of violations of the anti-drug program.

In 2001, the Sacramento Kings traded Williams to the Vancouver Grizzlies for Mike Bibby. (The team relocated to Memphis, Tennessee). With head coach Sidney Lowe, the team improved insignificantly. In 2002, General Manager Jerry West hired Hubie Brown out of retirement to coach the team. The team improved by a franchise record 28 wins in Brown's first season.

On August 2, 2005, Williams and teammate James Posey were two of thirteen players involved in the biggest trade in league history that saw them being dealt to the Miami Heat in exchange for shooting guard Eddie Jones.

Williams started at point guard for the Heat in the 2005–06 campaign. A knee injury caused him to miss some games. In the Game 6 of the Eastern Finals against the Detroit Pistons, Williams scored 21 points on 10 of 11 shooting in the series clinching game. Williams won his first NBA championship on June 20, 2006 when the Heat beat the Dallas Mavericks in the NBA Finals. During the finals, Williams averaged 12 points and 5 assists.

In the 2006–07 season, Jason was limited to 61 games, of those 55 he started. He averaged 10.9 points and 5.3 assists, which didn't meet his career averages of 11.7 and 6.5. His play dropped dramatically in the postseason, averaging 5.8 ppg and 3.5 assists per game. His struggles contributed to the Heat being swept by the Bulls in 4 games in the very first round of the playoffs.

In the 2007–08 season, Williams played 67 games while averaging 8.8 points and 4.6 assists per game. He shot 38% from the field, 87% from the line, 35% from beyond the arc, and averaged 1.3 steals per game. His best month was March where he averaged 13.7 points and 5.1 assists while shooting 43% from beyond the arc and 42% from the field. Also in March, he had 34 points vs Orlando, connecting on 5 threes. He had 2 double doubles: one against Phoenix and one against the Bucks. Both were 21 point, 10 assist performances.

In the summer of 2008, Williams reached an agreement with the Los Angeles Clippers on what was believed to be one-year deal. However, on September 26, 2008 Williams announced his retirement from the NBA after 10 years.

On August 19, 2009, Williams signed with the Orlando Magic.