Pinhead (also known as Lead Cenobite or the Hell Priest, among other names and titles) is a fictional character and the main antagonist of the Hellraiser franchise. The character first appeared as an unnamed figure in the 1986 Clive Barker novella The Hellbound Heart. When Clive Barker adapted the novella into the 1987 film Hellraiser, he referred to the character in early drafts as "the Priest" but the final film gave no name (he is credited as "Lead Cenobite" and only has approximately eight minutes of screentime). The production and make-up crew nicknamed the character "Pinhead"—derived from his bald head studded with nails—and fans accepted the sobriquet. The name was then used in press materials, tie-in media, and on-screen in some of the film's sequels, although Barker himself despises the moniker.

Pinhead is one of the leaders of the Cenobites, said to be humans who were transformed into demonic creatures devoted to the practice of experimental sadomasochism. They exist in an extra-dimensional realm that is Hell or one of many versions of Hell that co-exist. Cenobites are usually only summoned to Earth through puzzle boxes, such as one called the LeMarchand Configuration (known as the Lament Configuration in the film series).

In The Hellbound Heart, Pinhead is described as an androgynous being with a feminine voice. In 1987's Hellraiser, the character is portrayed by English actor Doug Bradley, who went on to reprise the role in seven subsequent Hellraiser films. In Hellraiser: Revelations (2011), Pinhead is played by Stephan Smith Collins, with Fred Tatasciore providing the character's voice. In Hellraiser: Judgment (2018), he is played by Paul T. Taylor. In the 2022 film, the character is portrayed by Jamie Clayton.

In the Hellraiser film series, Pinhead was once British soldier Captain Elliot Spencer, who became disillusioned with life and humanity during his experiences during World War I, leading him to summon the Cenobites and join their ranks. In Barker's Hellraiser comics published by BOOM! Studios, it is implied that Spencer was not the first Hell Priest or Pontifex and that others will be recruited to fill the role if he ever leaves or is destroyed. Additionally, Barker's novel The Scarlet Gospels indicates that there is debate on whether there has always been one Hell Priest existing for many millennia, or if the title and nature of the Hell Priest has been adopted by many different humans-turned-Cenobite across the centuries.

The Hell Priest's nature, and the motivations of the Cenobites, vary depending on the story. The character's appearance in 1987's Hellraiser marked a significant departure from the standard 1980s depiction of horror film villains, who tended to either be completely mute, or provide glib commentary while killing their victims. Instead, Pinhead was depicted as articulate and intelligent, speaking only when he deemed it necessary, capable of great evil but also bound by a personal code of honour (such as sparing the life of a young girl who summons him to Earth in Hellbound: Hellraiser II because he realises she acted as the pawn of another person). Barker drew influence from classical cinematic depictions of Count Dracula, in particular as portrayed by Christopher Lee.

According to Clive Barker and Doug Bradley, the earliest incarnation of Pinhead appeared in Hunters in the Snow, an original 1973 play directed by Barker, with Doug Bradley in the role of the Dutchman, an undead inquisitor, and torturer. A later film titled The Forbidden, which was shot in 16 millimetre and in black and white, included a prop in the form of a wooden block with six nails in it, which gave distorted shadow formations under different lighting angles. Years later, during the scripting of Hellraiser, the same design was applied to Pinhead's face to give the same effect.

After being disappointed with the way his material had been treated by the producers of the 1985 film Underworld, which Barker wrote (and which included a scene in which needles burst out of a character's skull), and then while working on the screenplay for Rawhead Rex (1986), Barker penned the 1986 novella The Hellbound Heart as his first step in directing a film by himself, introducing the Cenobites whom he also referred to as "sadomasochists from Hell". The following year, Barker adapted the novella into the first Hellraiser film, introducing the Cenobites to a wider audience. A Cenobite from the novella, described as having his head decorated by a gridwork pattern and jewelled pins, was depicted in the movie as having a similar appearance involving iron nails and operating as the apparent leader of his order of demons. Barker's sketches of the movie version of the character was different from the finished product, and had quills coming out of the top of his head, like Shuna Sassi in Nightbreed, but the budget wouldn't allow it. Instead the plan was to insert six-inch nails into his head. To find out where to put them, they used a drawing of a grid in a lifecast. Barker liked the symmetry of the pattern, so they kept it. But the nails felt crude and didn't feel right, and eventually it was decided to replace them with thin pins. The film credits him as "Lead Cenobite", but the make-up crew and production team referred to him as Pinhead, a name that was learned of and adopted by fans. The character is glibly referred to by the name "Pinhead" on-screen for the first time in Hellraiser III. The Pinhead name was used in press materials for the films and the various films to follow, as well as tie-in comic books published by Marvel Comics, including a crossover comic with Marshal Law, and a mini-series entitled Pinhead. Clive Barker did not care for the nickname, believing it did not suit the dignity of the villain.

During filming of the first Hellraiser film, actor Doug Bradley discussed the character with Clive Barker. Both agreed, as the novella indicated, that Pinhead was once human, though when he had lived and died was undecided. Bradley later concluded that while the Cenobites have been active for centuries, Pinhead was originally a person belonging to the 20th century, telling Fangoria: "To me, Pinhead is the chief Cenobite of the 20th century". This idea was expanded on in the second Hellraiser film, when the movie incarnation of Pinhead was said to have originally lived as a World War I officer named Elliot Spencer.