The Hulk is a superhero appearing in American comic books published by Marvel Comics. Created by writer Stan Lee and artist Jack Kirby, the character first appeared in the debut issue of The Incredible Hulk (May 1962). In his comic book appearances, the character, who has dissociative identity disorder (DID), is primarily represented by the alter ego Hulk, an immense, green-skinned, hulking brute, possessing a limitless degree of physical strength, and the alter ego Dr. Robert Bruce Banner, a physically weak, socially withdrawn, and emotionally reserved physicist, both of whom typically resent each other. Lee stated that the Hulk's creation was inspired by a combination of Frankenstein and Dr. Jekyll and Mr. Hyde.

Following his accidental exposure to gamma rays while saving the life of Rick Jones during the detonation of an experimental bomb, Banner is physically transformed into the Hulk when subjected to emotional stress, at or against his will. This transformation often leads to destructive rampages and conflicts that complicate Banner's civilian life. The Hulk's level of strength is usually conveyed proportionate to his anger level. Commonly portrayed as a raging savage, the Hulk has been represented with other alter egos, from a mindless, destructive force (War) to a brilliant warrior (World-Breaker), a self-hating protector (the Devil Hulk), a genius scientist in his own right (Doc Green), and a gangster (Joe Fixit).

Despite Hulk and Banner's desire for solitude, the character has a large supporting cast. This includes Banner's love interest Betty Ross, his best friend, Rick Jones, his cousin She-Hulk, and therapist and ally Doc Samson. In addition, the Hulk alter ego has many key supporting characters, like his co-founders of the superhero team the Avengers, his queen Caiera, fellow warriors Korg and Miek, and sons Skaar and Hiro-Kala. However, his uncontrollable power has brought him into conflict with his fellow heroes and others such as General Thunderbolt Ross, Betty's father. Despite this, he tries his best to do what's right while battling villains such as the Leader, the Abomination, the Absorbing Man, and more.

One of the most iconic characters in popular culture, the character has appeared on a variety of merchandise, such as clothing and collectable items that was inspired by real-world structures (such as theme park attractions), and been referenced in several media. Banner and the Hulk have been adapted into live-action, animated, and video game incarnations. The character was first played in live-action by Bill Bixby and Lou Ferrigno in the 1978 television series The Incredible Hulk and its subsequent television films The Incredible Hulk Returns (1988), The Trial of the Incredible Hulk (1989), and The Death of the Incredible Hulk (1990). In the 2003 film Hulk, the character was played by Eric Bana. In the Marvel Cinematic Universe (MCU), the character was first portrayed by Edward Norton in the film The Incredible Hulk (2008) and then by Mark Ruffalo in later appearances in the franchise.

The Hulk first appeared in The Incredible Hulk #1 (cover dated May 1962), written by writer-editor Stan Lee, penciled and co-plotted by Jack Kirby, and inked by Paul Reinman. Lee cites influence from Frankenstein and Dr. Jekyll and Mr. Hyde in the Hulk's creation:

It was patently apparent that [the monstrous character the] Thing was the most popular character in [Marvel's recently created superhero team the] Fantastic Four. ... For a long time, I'd been aware of the fact that people were more likely to favor someone who was less than perfect. ... It's a safe bet that you remember Quasimodo, but how easily can you name any of the heroic, handsomer, more glamorous characters in The Hunchback of Notre Dame? And then there's Frankenstein ... I've always had a soft spot in my heart for the Frankenstein monster. No one could ever convince me that he was the bad guy. ... He never wanted to hurt anyone; he merely groped his torturous way through a second life trying to defend himself, trying to come to terms with those who sought to destroy him. ... I decided I might as well borrow from Dr. Jekyll and Mr. Hyde as well—our protagonist would constantly change from his normal identity to his superhuman alter ego and back again.

Kirby also stated the Frankenstein inspiration stating, "I did a story called "The Hulk"– a small feature, and it was quite different from the Hulk that we know. But I felt that the Hulk had possibilities, and I took this little character from the small feature and I transformed it into the Hulk that we know today. Of course, I was experimenting with it. I thought the Hulk might be a good-looking Frankenstein. I felt there's a Frankenstein in all of us; I’ve seen it demonstrated. And I felt that the Hulk had the element of truth in it, and anything to me with the element of truth is valid and the reader relates to that. And if you dramatize it, the reader will enjoy it." Kirby also commented upon his influences in drawing the character, and recalled the inspiration of witnessing the hysterical strength of a mother lifting a car off her trapped child.

Lee has also compared Hulk to the golem of Jewish mythology. In The Science of Superheroes, Gresh and Weinberg see the Hulk as a reaction to the Cold War and the threat of nuclear attack, an interpretation shared by Weinstein in Up, Up and Oy Vey. This interpretation corresponds with other popularized fictional media created during this time period, which took advantage of the prevailing sense among Americans that nuclear power could produce monsters and mutants.