Mark A. Jackson (born April 1, 1965) is an American former professional basketball player who was a point guard in the National Basketball Association (NBA). He played college basketball for the St. John's Red Storm and was selected by the New York Knicks in the first round of the 1987 NBA draft with the 18th overall pick. He played in the NBA for the Knicks, Los Angeles Clippers, Indiana Pacers, Denver Nuggets, Toronto Raptors, Utah Jazz, and Houston Rockets in a career spanning from 1987 to 2004.

After retiring from playing basketball, Jackson became a broadcast commentator for ESPN and ABC alongside his former coach Jeff Van Gundy and play-by-play man Mike Breen. He also worked as an analyst for YES Network's New Jersey Nets games. In 2011, the Golden State Warriors hired Jackson as head coach. He coached the team for three seasons, but was fired in 2014 despite leading the Warriors to consecutive playoff appearances for the first time in over 20 years. Following this, he returned to ESPN and continued working as a commentator until his removal in 2023.

Mark Jackson grew up in the St. Albans neighborhood of Queens, New York City, New York. He was regarded as one of the nation's elite point guards in secondary school. Raised Catholic, he attended Bishop Loughlin Memorial High School in Brooklyn, New York City. He was a star player for the school's basketball team under coach Patrick Quigley. Jackson gained a reputation as a streetballer in New York.

Jackson was a college hoops star at St. John's University. While at St. John's, he played alongside Olympian and NBA All-Star Chris Mullin for two seasons. He credits Mullin with teaching him the importance of rigorous practice work in the gym.

While at St. John's, Jackson developed an unusual free-throw line ritual of extending his hand and "cupping" his thumb and index finger around the rim. This helped him stay focused on the rim while shooting foul shots. He continued this well into his pro career and it helped him to a career 77.0% free-throw percentage.

Jackson was the 18th pick of the 1987 NBA draft by the New York Knicks. He teamed with Patrick Ewing and Charles Oakley to turn the Knicks into a prime playoff team in the late 1980s and early 1990s. However, before the Knicks peaked and became regular playoff contenders, he was traded to the Los Angeles Clippers in 1992.

Jackson had a steady career with the Knicks, most notably under coach Rick Pitino, averaging 13.6 points and 10.6 assists per game in his rookie season, earning him the 1988 Rookie of the Year award, the lowest overall draft pick to win the award since Woody Sauldsberry in 1958. He was the only non-lottery pick to have won the award since the introduction of the system in 1985 until the 2016–17 season, where Malcolm Brogdon won the award as a second round pick.

In 1989, Jackson had another promising season for the Knicks, teaming with Ewing to lead them to the Atlantic Division title and the number-two seed in the East (behind the eventual champion Detroit Pistons, whom they swept 4–0 in the regular season), and making his lone All-Star Game appearance. After sweeping Charles Barkley's Philadelphia team in the opening round, the Knicks faced the upstart Chicago Bulls, led by Michael Jordan, in the Eastern Conference semifinals. Near the end of Game 2, Jackson en route to a fast-break layup in the fourth quarter looked back and stuck out his tongue at Jordan before finishing the layup; Jordan responded with a 40+ PPG average the remainder of the series, and led Chicago to a 4–2 series victory.