Rocky II is a 1979 American sports drama film written, directed by, and starring Sylvester Stallone. It is the direct sequel to Rocky (1976) and the second installment in the Rocky franchise. It also stars Talia Shire, Burt Young, Carl Weathers, and Burgess Meredith. Set immediately after the events of the original film, Rocky Balboa (Stallone), struggling to adjust to his newfound fame and family life, finds himself in a rematch fiercely demanded by Apollo Creed (Weathers).

Development of Rocky II began in 1977, after Stallone completed the screenplay. United Artists was reluctant to allow Stallone to direct after John G. Avildsen, the director of the first film, was unable to return. Stallone was eventually hired after refusing to allow the film to be made without him as director, and the returns of the rest of the cast were secured soon thereafter. Principal photography commenced in 1978, with filming held primarily on location in Philadelphia, during which Stallone sustained several injuries. The film is dedicated to the late Jane Oliver who was Stallone's first agent.

Rocky II was theatrically released in the United States by United Artists on June 15, 1979. The film received generally positive reviews from critics, with praise for its characterization, finale, and Stallone's performance. It grossed $200 million worldwide and $85 million in North America, making it the third highest-grossing film of 1979 domestically and the second highest-grossing film worldwide. A sequel, Rocky III, was released in 1982.

On New Year's Day 1976, world heavyweight boxing champion Apollo Creed has successfully defended his title in a split decision against challenger Rocky Balboa. He and Rocky are taken to the same hospital. Despite their agreement that there would be no rematch, Apollo challenges Rocky again that night to prove that Rocky going the distance with him was a fluke, but Rocky declines and retires from professional boxing. Balboa's girlfriend, Adrian, supports his choice as do his doctors who go on to reveal that Rocky will require surgery for a detached retina, a condition that could lead to permanent blindness. In a private moment, Rocky goes to see a recuperating Apollo, and asks whether Apollo gave his all in the fight; Apollo confirms that he did.

After Rocky is released from the hospital, he enjoys the benefits of his newfound celebrity status. An agent sees Rocky as a potential endorsement and sponsorship goldmine, and his sudden wealth encourages him to propose to Adrian; she happily accepts, and they marry in a small ceremony. Soon after, Adrian reveals that she is pregnant. Meanwhile, Apollo, fueled by hate mail claiming he fixed the fight in order to protect his reign as champ, becomes obsessed with the idea that a rematch is the only way to discredit Rocky's performance. Determined to rectify his boxing career's only blemish, Apollo demands his team do whatever necessary to goad Rocky out of retirement, despite the pleas of his friends and family that Rocky's ability to absorb punishment is too dangerous for his chances to successfully defend the title a second time.

Rocky at first seems unaffected by Apollo's smear campaign, but his limited education and poor manners soon lead him into financial problems. After several unsuccessful attempts to find employment, Rocky visits Mickey Goldmill, his trainer and manager, at his gym to talk about the possibility of facing Apollo. Mickey declines out of concern for Rocky's health, but he changes his mind after Apollo publicly insults Rocky. Adrian confronts Rocky about the danger of returning to boxing and reminds him of the risk to his eyesight, but he retorts that fighting is all he knows. Adrian backs down but refuses to support him.

Rocky and Mickey begin training, but Rocky is unfocused due to Adrian's disapproval. Adrian's brother, Paulie, confronts his sister about not supporting her husband, but Adrian faints during the confrontation and is rushed to the hospital, where she goes into labor. Despite being born prematurely, the baby is healthy, but Adrian falls into a coma. Rocky blames himself for what happened and refuses to leave her bedside until she wakes up, and will not go to see his new baby until the baby can be together with his mother. When Adrian comes out of her coma she finds Rocky by her bedside, and the couple is soon shown their new baby boy, who they name Robert "Rocky Jr". Adrian gives her blessing to the rematch and Rocky quickly gets into shape for the fight.

On Thanksgiving, the night of the match, Apollo makes a public goal of beating Rocky in no more than two rounds to prove the first match going the distance was a fluke. Unlike the first fight, Apollo has trained heavily. In order to protect his vulnerable eye, Rocky opts to fight right-handed rather than his natural southpaw, but this leaves him at a major disadvantage, as he is knocked down twice by Creed and outclassed for much of the fight. Going into the fifteenth and final round, Creed is well ahead on points and only needs to stay away from Balboa to win the fight by decision. However, Creed wants to win by knock-out in order to erase any doubts about his superiority and ignores his trainer's pleas to stay back.