Paul Michael Posluszny (/pəzˈlʌzni/; born October 10, 1984) is an American former professional football player who was a linebacker for eleven seasons in the National Football League (NFL), primarily with the Jacksonville Jaguars. He played college football for the Penn State Nittany Lions, winning the Chuck Bednarik Award twice and the Dick Butkus Award once. He was selected by the Buffalo Bills in the second round of the 2007 NFL draft. Following four years in Buffalo, Posluszny spent the remainder of his career with the Jaguars. Posluszny earned Pro Bowl honors during the 2013 season after leading the league in solo tackles. He was inducted into the College Football Hall of Fame in 2024.

Posluszny was born in Butler, Pennsylvania on October 10, 1984. He is of Polish descent (his surname in Polish means 'obedient'). He was a star halfback and linebacker at Hopewell High School in Hopewell Township, Beaver County, Pennsylvania. In 2002, his senior year, he helped lead the Vikings to the WPIAL championship with an 8–1 record, followed by the AAA State Championship.

Posluszny played football at Penn State University from 2003 to 2006. He debuted in the fifth game of his 2003 freshman season, and in the last game of the season made his first career start at Michigan State. During the season, he recorded 36 tackles, an interception (which he returned for a touchdown against Indiana), a fumble recovery, and was named to the Big Ten All-Freshman team by The Sporting News.

In 2004, he was named as a second-team All-Big Ten player as well as earning academic All-Big Ten honors. Prior to that season he changed to jersey No. 31, in honor of former Penn State players who had worn the number including All-Americans Shane Conlan and Andre Collins. He started in all 11 games and led his team with 104 tackles, and his 9.5 tackles per game average put him in a tie for fifth in the Big Ten. He also recorded 12 tackles for loss and three sacks, helping Penn State reach the national top 10 in scoring and total defense. In fact, the defense did not allow an opponent to reach over 21 points in a game all season. He also caught an interception, broke up three passes and forced a fumble on the season. He won the Big Ten Defensive Player-of-the-Week for his performance against Indiana, making 13 tackles and playing a key role in Penn State's goal-line stand to ensure the win.

In 2005, Posluszny became the first junior captain for Penn State since Mike Reid and Steve Smear in 1968. He posted 116 tackles on the season, 14 for loss, and 4 sacks, including a 22-tackle game against Northwestern. He was named Big Ten Defensive Player-of-the-Week a record-breaking three consecutive times. He then joined LaVar Arrington as the second Penn State player to win both the Chuck Bednarik and Dick Butkus Awards as the College Defensive Player and Linebacker of the Year respectively, and was named as a member of the 2005 All-America Team. He helped lead the Penn State Nittany Lions to a win in the 2006 Orange Bowl against Florida State but left the game in the fourth quarter after partially tearing two ligaments in his knee; the injury did not require surgery. He subsequently announced that he planned to return to Penn State for his senior year of college, rather than declare himself eligible for the 2006 NFL draft, a decision which, a year later, was considered "a boon," with Posluszny completing the 2006 season with 116 tackles and a school-high career total 372 tackles.

In 2006, he continued captaincy, along with Levi Brown. Jack Ham, former All-American Linebacker at Penn State, said that Posluszny was the greatest linebacker to ever play at Penn State. On November 4, 2006, he broke Greg Buttle's school record for tackles. Posluszny had 372 career tackles, with 116 of them coming during that season, including 9.5 tackles for loss, three sacks, and two forced fumbles. (The Penn State tackle record was surpassed shortly after by fellow linebacker Dan Connor.) Posluszny won the 2006 Chuck Bednarik Award to become only the second person (after Pat Fitzgerald) to win the award two times. Posluszny was also named a member of the 2006 All-America Team, the first Penn State linebacker to be a two-time Associated Press All-American.

Posluszny graduated a semester early in December 2006 with a Bachelor of Science in finance and a 3.57 GPA. He is a two-time ESPN The Magazine Academic All-American and was named 2006 Academic All-American of the Year. He was also a finalist for the Draddy Trophy, which is presented to the nations' top student-athlete.

Posluszny was inducted into the College Football Hall of Fame in 2024.