Joseph Thomas Barrett IV (born January 23, 1995) is an American football coach and former quarterback who is the quarterbacks coach for the Chicago Bears of the National Football League (NFL). He played college football for the Ohio State Buckeyes, earning third-team All-American honors in 2014. Barrett was signed as an undrafted free agent by the NFL's New Orleans Saints in 2018. He also played for the Seattle Seahawks, Pittsburgh Steelers, and Edmonton Elks.

After retiring as a player, Barrett pursued a coaching career and was an assistant coach for the Detroit Lions from 2022 to 2024.

Barrett attended S. H. Rider High School in Wichita Falls, Texas, where he was a three-sport athlete in football, basketball, and track. He played as a dual-threat quarterback for the Raiders football team. As a junior, he rushed for over 1,500 yards and passed for over 1,600 yards, totaling 23 touchdowns. In his senior season, he rushed for 569 yards with seven touchdowns and passed for 784 yards and five touchdowns before tearing his ACL in October, which ended his high school career prematurely. In spring 2011, Barrett joined the school's track & field team, recording a personal-best time of 11.10 seconds in the 100-meter dash at the Iowa Park Relays, winning the event, while also running the second leg in the 4 x 400-meter relay, helping them earn a second-place finish with a time of 3:46.05 minutes.

Barrett was ranked by the Rivals.com recruiting network as a four-star recruit and the seventh best dual-threat quarterback in his class. He committed to Ohio State University in April 2012.

Barrett redshirted as a freshman at Ohio State in 2013. Barrett was expected to be the backup quarterback to senior Braxton Miller in 2014. However, he became the starter after Miller was forced to miss the season due to injury. On November 29, during the Ohio State-Michigan matchup, Barrett went down with what was later determined to be a broken ankle early in the fourth quarter. The injury happened on a run play, with Ohio State leading 28–21, after Barrett had thrown for 176 yards and a touchdown while also rushing for 89 yards and two touchdowns. Ohio State went on to win the game with Cardale Jones at quarterback. Barrett was cited in the weeks before the injury as a potential Heisman Trophy contender but ended up finishing fifth in the voting. His injury prevented him from returning during the 2014 season, but he had a successful surgery and was expected to be available in a limited capacity for spring practice. Ohio State went on to win their next game against Wisconsin, the 2015 Sugar Bowl against Alabama, and the 2015 CFP National Championship, behind the play of third-string quarterback Cardale Jones.

As a redshirt sophomore in 2015, Barrett passed for 992 yards, 11 touchdowns, and four interceptions, splitting time with Jones. As a redshirt junior in 2016, he passed for 2,555 yards, 24 touchdowns, and seven interceptions. Barrett returned to Ohio State for his final season of eligibility in 2017. As a redshirt senior in 2017, he passed for 3,053 yards, 35 touchdowns, and nine interceptions.

Barrett was named Conference Freshman of the Week seven times and received the Big Ten's Thompson–Randle El Freshman of the Year award. He received the Big Ten's Griese–Brees Quarterback of the Year award in 2014, 2016 and 2017. Barrett was named First-team All-Big Ten in 2014, 2016 and 2017 by both conference coaches and media. Barrett earned Big Ten Offensive Player of the Week honors nine times.

Barrett is the only quarterback on either side of the Michigan-Ohio State rivalry to go 4–0 as a starter.