1990–91 Princeton Tigers men's basketball team

The 1990–91 Princeton Tigers men's basketball team represented Princeton University in NCAA Division I men's college basketball during the 1990–91 NCAA Division I men's basketball season. Their head coach was Pete Carril, and the team captain was Kit Mueller. The team played its home games in the Jadwin Gymnasium on the university campus in Princeton, New Jersey. The team was the undefeated champion of the Ivy League, which earned them an automatic invitation to the 64-team 1991 NCAA tournament, where they were seeded eighth in the East Region.

In December, undefeated Princeton handed Rutgers their first loss. The team posted a 24–3 overall record and a 14–0 conference record using the Princeton offense. When the team beat 55–27 on January 11, 1991, it established a new National Collegiate Athletic Association Division I record for fewest points allowed (since 1986), breaking its own record set the prior year. The record would last until March 2, 1992. On February 8, 1991, against , Sean Jackson made all five of his three-point field goal attempts, which tied the Ivy League single-game record for most made without a miss set three years earlier by Princeton Tigers Dave Orlandini and Bob Scrabis. These stood as unsurpassed as the Ivy League record until future Princeton Tigers head coach Sydney Johnson made all six for Princeton on February 28, 1997. The Tigers led 30–25 at halftime, but lost on a shot in the final second of regulation play. Princeton's number eight seed was a record for the highest seed by an Ivy League school at the time. During the undefeated conference game season, Jackson established the Ivy League single-season conference games record with 56 three-point field goals made, which stood at least 25 seasons.

During the season, the team spent six weeks (one week in mid December and the final five weeks of the season) of the seventeen-week season ranked in the Associated Press Top Twenty-five Poll, peaking at number eighteen where it ended the season. The team finished the season ranked twentieth in the final UPI Coaches' Poll. The team completed the first undefeated Ivy season by any team since the 1975–76 Princeton Tigers men's basketball team.

The team was led by first team All-Ivy League selections Jackson and Mueller, who repeated as the Ivy League Men's Basketball Player of the Year while earning first team Academic All-America recognition from College Sports Information Directors of America. Jackson led the Ivy League in three point shooting percentage in conference games with a 55.4% average and established the Ivy League single-season record for conference games with 56 made.