Plot
Bobby Boucher is a socially inept, stuttering water boy with hidden anger issues due to constant teasing and excessive sheltering by his mother, Helen (Kathy Bates). He became the water boy for the (fictional) University of Louisiana Cougars after being told his father died of dehydration in the Sahara while serving in the Peace Corps. However, the players always torment him and the team's head coach, Red Beaulieu (Jerry Reed), eventually fires him for "disrupting" his practices. Bobby then approaches Coach Klein (Henry Winkler) of the South Central Louisiana State University Mud Dogs and asks to work as the team's water boy. Coach Klein has been coach of SCLSU for years without success, after his brilliant playbook was stolen by Red Beaulieu.

Bobby's mother Helen tells Bobby of the evils of football and forbids him to play. After being picked on again by his new team, Coach Klein encourages Bobby to strike back, which leads to him tackling and knocking out the team's quarterback. Coach Klein convinces Bobby to enroll as a student at SCLSU and play for the team, which he agrees to do as long as nobody tells his mother after Coach Klein shows Bobby his tattoo of Roy Orbison, encouraging him to clandestinely go against his mother's wishes.

Bobby quickly becomes one of the most feared linebackers in college football, hitting opposing players with injury-causing force. The Mud Dogs manage a winning streak and earn a trip to the annual Bourbon Bowl to face the Cougars and Coach Beaulieu. Bobby's newfound fame also allows him to rekindle a relationship with his childhood friend and crush, Vicki Vallencourt (Fairuza Balk), who has been in prison multiple times. However, Helen forbids Bobby from seeing her again.

Coach Beaulieu reveals that Bobby never finished high school, making him ineligible for college and football. However, Bobby manages to pass his GED exam, despite his mother's objections about him going back to college. She then fakes falling ill to keep Bobby from playing, but eventually relents after witnessing the town residents' support for Bobby. The next day, Helen tells Bobby the truth what really happened to his father and why she was faking her illness. Years ago, he changed his name to Roberto and left her for a voodoo priestess, while she was pregnant. This in turn lead Helen to excessively sheltering him all his life. She was afraid Bobby was going to leave her, too, and tried to keep him all to herself by hiding him from everyone else who depended on him. Helen realizes the best thing for her to do is let him go since he has made a lot of friends and encourages him to play in the Bourbon Bowl.

Arriving at halftime of the Bourbon Bowl with Helen and Vicki, Bobby manages to encourage the losing Mud Dogs to make a comeback. The team admits that he has become the heart and soul of the Mud Dogs. Seeing the overwhelming support at the Bourbon Bowl, Helen changes her mind about football being for the devil. With Bobby's help, Coach Klein overcomes his fear of Red Beaulieu by imagining him as something he's not afraid of (i. e. a baby and a cocker spaniel). This helps Klein create spectacular new plays that allow the Mud Dogs to catch up. Helen helps the cheerleaders out by making coffee and it helps keep their energy up as they cheer their fans on to rally, while Vicki is seen giving out water to the Mud Dogs. During the final play, Bobby throws a touchdown pass and the Mud Dogs win the Bourbon Bowl. Bobby is named the MVP of the game.

Sometime later, Bobby and Vicki get married and are heading to the riding lawn mower. Although Helen still has some reservation on Vicki, she admits he's got a fine woman who'll take care of him. On their way out Bobby's father, Roberto, makes an unexpected appearance, telling him that he heard from ESPN that he may go to the NFL. Bobby tells him that he's not going to the NFL because he wants to stay in school and graduate. Roberto tries to convince Bobby to leave school and go to the NFL, hoping to personally profit as his father. However, an enraged Helen charges in and tackles him, causing cheers from the attendants. Bobby and Vicki leave to consummate their marriage.

Critical reception
The Waterboy received mixed to negative reviews from critics. On review aggregator site Rotten Tomatoes, the critics gave the film a rating of 32%, or 4.6/10, and the audience review gave it 75%, the site's consensus being "The Waterboy is an insult to its genre with low humor and cheap gags." On Metacritic, the film holds a rating of 41%, indicating "Mixed or average reviews. " The film grossed $185,991,646 worldwide from a $20 million budget  The film also appears on critic Roger Ebert's "Most Hated" list.