Isaiah Jamar Thomas (born February 7, 1989) is an American professional basketball player for the Salt Lake City Stars of the NBA G League.

After electing to forgo his senior year of college, Thomas was selected by the Sacramento Kings with the final pick in the 2011 NBA draft.

In the 2016–17 season, he led the Celtics to the first seed of the Eastern Conference, had the third-highest points-per-game average in the league, and finished fifth in MVP voting.

Thomas went on to play for the Los Angeles Lakers, Denver Nuggets, Washington Wizards, New Orleans Pelicans, Dallas Mavericks, Charlotte Hornets, and Suns again, along with several stints in the NBA G League.

Thomas was born months before the finals took place but his father had warmed to the name and his mother consented on the condition that the Biblical spelling of Isaiah was utilized.

On March 12, 2011, Thomas scored 28 points and hit a game-winning buzzer beater in overtime to lead the Huskies to victory over Arizona in the championship game of the Pac-10 tournament.

[16] On March 1, 2012, Thomas was named the Western Conference NBA Rookie of the Month after averaging 12.2 points and 4.4 assists per contest in February.

On April 2, 2012, Thomas was once again named Western Conference NBA Rookie of the Month after posting averages of 13.6 points and 4.9 assists per contest in March.

[22] Thomas was immensely popular in his three seasons in Sacramento; his show of solidarity and frequent appearances at City Council meetings during the Kings' relocation saga, in particular, endeared him to many fans.

[26] After missing eight games with an ankle injury, Thomas returned to action on December 12, 2014, scoring 10 points in the Suns' 105–103 loss to the Detroit Pistons.

[36] Thomas made his debut for the Celtics on February 18, 2015, in a 118–111 overtime loss to the Los Angeles Lakers, scoring 21 points off the bench.

As a result of his sixth-man role with both Phoenix and Boston in 2014–15, Thomas finished second in the NBA Sixth Man of the Year Award voting.

He led the NBA in scoring (32.9 ppg) and tied for fifth in the East in assists (6.9 apg) for the month as the Celtics went 10–4 to take over first place in the Atlantic Division.

[61] The following day, Thomas broke Havlicek's team record with a 41st straight 20-point game; he scored 29 points in a 104–103 loss to the Chicago Bulls.

Thomas returned to Boston for Game 1 of the Eastern Conference Semifinals and helped the Celtics defeat the Washington Wizards 123–111.

[69] According to ESPN, during Game 1, "Thomas lost a front tooth following an inadvertent elbow from Otto Porter, requiring surgery to replace it and fix two other shifted teeth.

[52] Two days later in Game 2, Thomas scored 53 points—the second-highest total in Celtics playoff history—to help Boston win 129–119 in overtime and take a 2–0 lead in the series.

[70] In Game 7, Thomas scored 29 points and had 12 assists to help the Celtics advance to the Eastern Conference Finals for the first time since 2012 with a 115–105 victory.

After the Celtics lost the first two games of the 2017 Eastern Conference Finals to the Cleveland Cavaliers, Thomas was ruled out for the rest of the postseason with a hip injury.

[72] In a statement, the Celtics said: Isaiah Thomas will miss the remainder of this year's postseason following re-aggravation of a right femoral-acetabular impingement with labral tear during Game 2 of the Eastern Conference Finals against Cleveland.

[74] On August 22, 2017, Thomas was traded, along with Jae Crowder, Ante Žižić, and the Brooklyn Nets' unprotected 2018 first-round draft pick, to the Cleveland Cavaliers in exchange for Kyrie Irving.

[75] However, during the post-trade physical examination by Cleveland staff, concerns were raised about the health of Thomas' previously injured right hip.

[76] As a result, eight days after the deal was announced, the Celtics agreed to send the Cavaliers a 2020 second-round draft pick via the Miami Heat to complete the trade.

[77] In September 2017, TheAthletic.com reported that Thomas had been playing with a number of secondary issues in his right hip, such as a loss of cartilage and some arthritis, for several seasons.

[78] Thomas opted to pursue rehabilitation rather than surgery for the hip because he believed that the lengthy post-surgery recovery period would cause teams to be less willing to offer him large contracts during his upcoming free agency.

[68][79] On January 2, 2018, Thomas made his long-awaited debut for the Cavaliers, scoring 17 points in 19 minutes off the bench in a 127–110 victory over the Portland Trail Blazers.

[93] After his recovery from hip surgery, Thomas made his debut for the Nuggets on February 13, 2019, scoring all eight of his points in the third quarter of Denver's 120–118 victory over the Sacramento Kings.

[103] He made his debut for the team on December 15, scoring 42 points, eight assists, and six rebounds in 42 minutes during a 131–127 loss to the Fort Wayne Mad Ants.

[104] On December 17, 2021, Thomas signed a 10-day contract with the Los Angeles Lakers to return to the franchise for a second time after the team was granted a hardship exception.

[121] On January 28, 2025, Thomas rejoined the Salt Lake City Stars,[122] scoring 40 points in his first appearance back with the team.