"Brother from the Same Planet" is the fourteenth episode of the fourth season of the American animated television series The Simpsons. It first aired on Fox in the United States on February 4, 1993. In the episode, Bart, furious with Homer for taking too long to pick him up from soccer practice on a rainy day, turns to the Bigger Brothers Agency, which pairs up fatherless boys with adult male role models (a parody of the Big Brothers of America). Meanwhile, Lisa becomes addicted to the Corey hotline, a phone service where television fans can listen to the voice of a teen idol.

The episode was written by Jon Vitti and directed by Jeffrey Lynch. The producers tried to cast Tom Cruise for the role of Tom, but Cruise declined and they chose Phil Hartman instead. "Brother from the Same Planet" received favorable reception in books and in the media; a contemporary review in Entertainment Weekly said it "may be the best Simpsons show ever" and it was named one of the five best episodes of the series by the writers of King of the Hill.

On a rainy day, Bart waits for Homer to pick him up from soccer practice. However, Homer forgets to pick Bart up for many hours; by the time Homer finally picks Bart up, Bart is soaked from the rain. Furious with Homer, Bart goes to the Bigger Brothers Agency, a mentor program which pairs up fatherless boys with positive male role models. Bart claims that his father was an alcoholic gambler who abandoned him (which is true, but Bart exaggerates the details). The receptionist pairs him up with Tom, a handsome military test pilot. Bart and Tom enjoy a variety of activities together, though Bart begins to feel guilty for taking up Tom's time despite not actually being fatherless. Homer finds out about Tom and confronts Bart. Homer decides to get revenge by becoming a Bigger Brother himself. A poor young boy named Pepi comes to the agency and asks if he can have a Bigger Brother. Taking pity on Pepi, Homer decides to become his Bigger Brother.

Meanwhile, Marge discovers that the cost of her family's monthly phone bill is abnormally high. She soon finds out why — Lisa has been making lengthy calls to the Corey hotline, a premium rate phone service where fans can listen to the voice of a teen heartthrob. Lisa promises to stop making calls to the hotline on the family's phone. However, she continues to call the hotline by using phones in Dr. Hibbert's office, the Springfield Retirement Castle, and Springfield Elementary School. After Principal Skinner sees Lisa using the school's phone, he calls a meeting with Lisa and Marge. Marge suggests that Lisa try to go until midnight without calling the hotline; if she can do so, she will have conquered her addiction. Lisa is tempted throughout the rest of the day, but she ultimately beats her addiction.

Some time later, Homer, Pepi, Bart, and Tom attend Bigger Brothers Day at Marine World, where the Bigger Brothers and their boys attend to celebrate. Homer runs into Bart and Tom and reveals to Tom that he is Bart's father. Tom punches Homer, leading to a brawl between the two men. The fight rages across Springfield and ends when Homer lands on a fire hydrant, severely injuring his back. Homer is sent to a hospital on a stretcher. Feeling remorseful, Bart decides to forgive Homer. Tom laments how he will miss being a Bigger Brother, while Pepi is sad over losing his Bigger Brother. Bart suggests Tom become Pepi's big brother; they happily agree and walk into the sunset holding hands. After Homer recovers, Bart asks Homer to teach him how to fight.

The episode was written by Jon Vitti and directed by Jeffrey Lynch. It originally aired in the United States on February 4, 1993, on Fox. The role of Tom was written for Tom Cruise. However, when offered the part, Cruise repeatedly turned it down, so the producers used Phil Hartman. Corey is a composite of Corey Feldman and Corey Haim, known as The Two Coreys. Pepi was based on the title character of the daily comic strip Dondi.

In one scene of the episode, Bart and Tom watch a fictitious episode of The Ren & Stimpy Show. Gracie Films contacted Nickelodeon to get authorization to use Ren and Stimpy for that sequence. Nickelodeon was strict about what The Simpsons was allowed to do, and they were not allowed to make the duo uncharacteristically savage as they wanted. Animators from Games Animation who worked on the series, including Chris Reccardi, offered to do the layouts of Ren and Stimpy for the episode. Another show Bart watches, Tuesday Night Live, is a parody of NBC's Saturday Night Live. Krusty appears in a sketch called "The Big Ear Family", and says that the sketch goes on for twelve more minutes, even though the joke's punchline has already been established. That was Vitti's way of criticizing Saturday Night Live for having overlong sketches with thin joke premises. The sequence originally had a longer version of the Tuesday Night Live band playing into the commercial break, but it was cut because Vitti, who was a writer on Saturday Night Live during the 1985–86 season along with fellow Simpsons writers George Meyer and John Swartzwelder, did not want to come off as being bitter.

The writers were looking for an ending, and executive producer Sam Simon suggested they watch The Quiet Man. The writers came in on a Saturday to watch it, and were inspired by the fight scene between John Wayne and Victor McLaglen to do a fight scene between Homer and Tom. The scene was difficult for the producers to sound-mix because they wanted it to sound comedic but not horrifying. They discovered that the more realistic the effects used sounded, the funnier the scene became. The producers tried all sorts of different sound effects for when Homer cracks his back on the fire hydrant and chose the tiniest realistic sound, because they believed that it was the most painful and "hilarious".