2017–18 Cleveland Cavaliers season

The 2017–18 Cleveland Cavaliers season was the 48th season of the franchise in the National Basketball Association (NBA). The Cavaliers entered the season as runners-up in the 2017 NBA Finals, where they lost to the Golden State Warriors in five games. This was the Cavaliers' first season without Kyrie Irving since the 2010–2011 season, as he was traded to the Boston Celtics during the offseason per his request. This trade ended the superteam era of the Cavaliers.

The Cavaliers clinched their playoff berth for the fourth consecutive season since LeBron James' return to Cleveland for the 2014–15 season. In the playoffs, the Cavaliers defeated the Indiana Pacers in seven games in the First Round, then swept the top-seeded Toronto Raptors in four games in the Semi-finals, before finally defeating the Boston Celtics in seven games in the conference finals. Cleveland reached the NBA Finals for the fourth straight season, despite having an injury filled roster throughout the span of the 2017-2018 season, but were swept by the defending NBA champions Golden State Warriors in four games, the first Finals sweep that occurred since 2007, when the LeBron-led Cavs were also swept by the San Antonio Spurs. It was the fourth year in a row the two teams had faced off in the Finals, and the eighth consecutive season in which James had made it to the championship round. It was also James' final season with the Cavaliers, as he opted out of his contract during the subsequent offseason and again left the Cavaliers to sign with the Los Angeles Lakers, his second time leaving his hometown team after doing so in 2010 to join the Miami Heat.

With the loss in the Finals for the second consecutive year, the Cavaliers had become the first team since the then-New Jersey Nets in 2003, the team led by Hall of Famer Jason Kidd, to lose back-to-back Finals.

This marked the last season the Cavaliers made the playoffs until their 2022–23 season.