The 1998–99 Phoenix Suns season was the 31st season for the National Basketball Association's Phoenix Suns. During the offseason, the Suns signed free agent Tom Gugliotta while acquiring Luc Longley from the Chicago Bulls. Head coach Danny Ainge returned for his third season as the team finished tied for third in the Pacific division with a record of 27–23 in the shortened lockout season. The 6th-seeded Suns made the playoffs for the 11th consecutive season before being swept in the first round to the 3rd-seeded and Pacific winner-Portland Trail Blazers, three games to zero. All home games were played in America West Arena.

Starting point guard Jason Kidd finished the regular season leading the league in assists per game at 10.8. Three Suns would average 16 points or more per game, with Gugliotta notching 17, Kidd 16.9 and Clifford Robinson at 16.4 per game. Kidd led the league in total minutes played and was third in total steals, before being selected to both the All-NBA and All-Defensive First Teams. Following the season, Danny Manning was traded to the Orlando Magic, who then traded him to the Milwaukee Bucks two weeks later, and George McCloud signed as a free agent with the Denver Nuggets.