Norman Virgil Osborn is a character appearing in American comic books published by Marvel Comics. Created by writer Stan Lee and artist Steve Ditko, the character first appeared in The Amazing Spider-Man #14 (July 1964) as the first and best-known incarnation of the Green Goblin. He has since endured as one of the superhero Spider-Man's most prominent villains and is regarded as one of his three archenemies, alongside Doctor Octopus and Venom.

Norman Osborn is the amoral industrialist head of science conglomerate Oscorp and the father of Harry Osborn, the best friend of Spider-Man's alter ego Peter Parker. Osborn, in part due to the death of his wife, is obsessed with attaining as much power as possible and maintains a cold disposition towards Harry, openly favoring Peter for his intellect. In his origin story, Osborn is exposed to an experimental formula that enhances his physical abilities and intellect at the cost of his sanity. He becomes a criminal mastermind known as the Green Goblin and uses an arsenal of advanced, Halloween-themed equipment, including grenade-like Pumpkin Bombs, razor sharp bats, and a flying Goblin Glider, to terrorize New York City.

Osborn has been part of defining Spider-Man stories, including the murder of Gwen Stacy—Peter's love interest—in "The Night Gwen Stacy Died" (1973) and the orchestration of the "Clone Saga" (1994–1996). While his primary foe is Spider-Man, Osborn has often come into conflict with Iron Man, Captain America and other superheroes in the Marvel Universe. Although Osborn sometimes works with other supervillains such as Doctor Doom and Loki and groups like the Sinister Six and the Dark Avengers, these relationships often collapse due to his obsessive desire for unbridled power. Osborn's largest overarching story came during the line-wide "Dark Reign" and Siege comic book events, during which he originated the persona of the Iron Patriot. On being stripped of his "sins" by Kindred on behalf of A.I. Harry Osborn as revenge for selling human Harry's soul to Mephisto, the forcibly-repentant Norman becomes the superhero Gold Goblin, starring in Gold Goblin.

The character has been in various top villain lists as one of Spider-Man's greatest enemies and one of the greatest comic book villains of all time. The character's popularity has seen him appear on a variety of merchandise, inspire real-world structures (such as theme park attractions) and be referenced in a number of media. He has been adapted to serve as Spider-Man's adversary in live-action, animated, and video game incarnations. Willem Dafoe played the character in Sam Raimi's Spider-Man film trilogy and reprised the role in the Marvel Cinematic Universe film Spider-Man: No Way Home (2021), while Chris Cooper played the character in the film The Amazing Spider-Man 2 (2014).

Marvel Comics editor and head writer Stan Lee and artist Steve Ditko are credited with creating the character; they collaborated on how the character would be portrayed. According to Ditko: "Stan's synopsis for the Green Goblin had a movie crew, on location, finding an Egyptian-like sarcophagus. Inside was an ancient, mythological demon, the Green Goblin. He naturally came to life. On my own, I changed Stan's mythological demon into a human villain".

The Green Goblin debuted in The Amazing Spider-Man #14. At this time his identity was unknown, but he proved popular and reappeared in later issues, which made a point of his secret identity. According to both Stan Lee and John Romita, Sr., who replaced Ditko as the title's artist, Lee always wanted the Green Goblin to be someone Peter Parker knew, while Ditko wanted his civilian identity to be someone who had not yet been introduced. Lee elaborated: "Steve wanted him to turn out to be just some character that we had never seen before. Because, he said, in real life, very often a villain turns out to be somebody that you never knew. And I felt that that would be wrong. I felt, in a sense, it would be like cheating the reader. ... if it's somebody you didn't know and had never seen, then what was the point of following all the clues? I think that frustrates the reader". However, Lee prefaced this statement by admitting that, due to his self-professed poor memory, he may have been confusing the Green Goblin with a different character, and in an earlier essay he had said that he could not remember whether Norman Osborn being the Green Goblin was his idea or Ditko's. Ditko has maintained that it was his idea, even claiming that he had decided on it before the first Green Goblin story was finished. Though Osborn would not be introduced by name until The Amazing Spider-Man #37, Ditko has said that a character he drew in the background of two panels in issue #23 was intended to be Osborn, seeded in advance of the reveal. Lending credence to Ditko's claim, this then-nameless character—a member of a businessmen's club and a friend of J. Jonah Jameson—reappeared in a scene in The Amazing Spider-Man #25, visiting Jameson at his office, then again in the businessman's club in #26 and #27, and when Norman was formally introduced in issue #37, he too was stated to be a member of the club and friend of Jameson's.

Ditko left the series with issue #38, just one issue after Norman Osborn was introduced as the father of Harry Osborn. The first issue without Ditko saw the Green Goblin unmasked. John Romita, Sr., who replaced Ditko as the title's artist, recalled:

Stan wouldn't have been able to stand it if Ditko did the story and didn't reveal that the Green Goblin was Norman Osborn. I didn't know there was any doubt about Osborn being the Goblin. I didn't know that Ditko had just been setting Osborn up as a straw dog. I just accepted the fact that it was going to be Norman Osborn when we plotted it. I had been following the last couple of issues and didn't think there was really much mystery about it. Looking back, I doubt the Goblin's identity would have been revealed in Amazing #39 if Ditko had stayed on.