Richard Marvin Butkus (December 9, 1942 – October 5, 2023) was an American professional football linebacker, sports commentator, and actor. He played football for the Chicago Bears of the National Football League (NFL) from 1965 to 1973. He was invited to eight Pro Bowls in nine seasons, named a first-team All-Pro five times, and was twice recognized by his peers as the NFL's Defensive Player of the Year. Butkus was renowned as a fierce tackler and for the relentless effort with which he played. He is widely regarded as one of the greatest and most intimidating linebackers in professional football history.

Butkus was born in Chicago and played his entire football career in his home state of Illinois, which began at Chicago Vocational High School. He was a linebacker and a center for the Illinois Fighting Illini. He was a twice consensus All-American, and he led the Illini to a Rose Bowl victory in 1963 and was deemed the most valuable player in the Big Ten Conference. Butkus was named college football's Lineman of the Year in 1964. He was inducted into the College Football Hall of Fame in 1983.

Butkus was selected by the Bears as the third overall pick in the 1965 NFL draft. He soon established himself as a ball hawk with his penchant for forcing turnovers. During his NFL career, he intercepted 22 passes and recovered 27 fumbles (a record when he retired), and he was responsible for causing many more fumbles with his jarring tackles. His tackling ability earned him both admiration and trepidation from opposing players. In 2009, the NFL Network named Butkus the most feared tackler of all time.

Butkus is credited with having defined the middle linebacker position and is still viewed as the "gold standard by which other middle linebackers are measured". In his honor, the Butkus Award recognizes American football's most outstanding linebacker. He was inducted into the Pro Football Hall of Fame in 1979, and his No. 51 jersey was retired by the Bears. Following his playing career, Butkus worked in acting, sports commentary, and celebrity endorsement. He was active in philanthropy through the Butkus Foundation, which manages various charitable causes.

Butkus was born in Chicago, the youngest of eight children, and first to be born in a hospital. He was a very large baby, weighing 13 pounds 6 ounces (6.1 kg) at birth. His father John, a Lithuanian immigrant to Ellis Island who spoke broken English, was an electrician and worked for the Pullman-Standard railroad car manufacturing company. His mother, Emma, worked 50 hours a week at a laundry. Butkus grew up in the Roseland neighborhood on Chicago's South Side. He was a fan of the Chicago Cardinals of the National Football League (NFL) and attended their games at Comiskey Park. His older brother Ron played football for three colleges and tried out for the Cardinals before quitting due to a bad knee. For four years starting at age 15, Butkus worked with his four brothers as a mover.

Butkus played high school football as a fullback, linebacker, punter, and placekicker for coach Bernie O'Brien at Chicago Vocational High School. He averaged five yards per carry as a fullback, but preferred playing linebacker, where he made 70 percent of his team's tackles. In Butkus's first year on the varsity team, Chicago Vocational surrendered only 55 points in eight games. In 1959, he was the first junior to be honored by the Chicago Sun-Times as Chicago's high school player of the year. Injuries limited his play as a senior, but he was still heavily recruited by colleges to play football.

In the summer of 1960, Butkus was the starting catcher on a Chicago Park District baseball team known as the Sundodgers. An article in the Daily Calumet credits Butkus with driving in all of the Sundodgers' runs in a loss by hitting a home run to center field.

Butkus chose to attend the University of Illinois, and played center and linebacker from 1962 through 1964 for the Illinois Fighting Illini football team. He initially wanted to play for the Notre Dame Fighting Irish; however, the team frowned upon married players at the time. In his first year on the varsity team, he was named to the 1962 All-Big Ten Conference football team as the third-team center by the Associated Press (AP) and second-team center by United Press International (UPI). In 1963, Illinois compiled an 8–1–1 record and defeated Washington in the 1964 Rose Bowl. Butkus was named the team's most valuable player for the season, and was awarded the Chicago Tribune Silver Football as the Big Ten's most valuable player. He was a unanimous choice as a center for the 1963 College Football All-America Team, earning first-team honors from all seven major selectors.