The Hellfire Club is a fictional society appearing in American comic books published by Marvel Comics. The Hellfire Club often comes into confrontation with the X-Men mutant superhero team. Although the Club appears to merely be an international social club for wealthy elites, its clandestine Inner Circle seeks to influence world events and advance their agenda.

The Hellfire Club was created in 1980 by the Uncanny X-Men writer/artist duo of Chris Claremont and John Byrne, who were inspired by a 1966 episode of the British television series The Avengers ("A Touch of Brimstone"). The name "Hellfire Club" was a popular name for gentlemen's clubs in the 18th century. The Inner Circle's hierarchy is modeled on the pieces of a chess set, with Black and White sets of Kings, Queens, Bishops and Rooks.

The Hellfire Club and its Inner Circle were introduced in "The Dark Phoenix Saga", attempting to subvert the X-Men's Jean Grey. This incarnation, composed most notably of Black King Sebastian Shaw and White Queen Emma Frost, would remain prominent for many years. After their initial confrontations, the Hellfire Club and the X-Men settled into an uneasy alliance. This eventually changed as endless power struggles perpetuated a series of upheavals within the Inner Circle. The club has appeared in two X-Men animated series (X-Men: The Animated Series and Wolverine and the X-Men), both times being renamed as simply The Inner Circle, due to the aversion of using the term "hellfire" in a children's cartoon. Members of the Hellfire Club appeared in 2011's X-Men: First Class as the main villains, led by Sebastian Shaw, Emma Frost, Azazel, and Riptide. The Hellfire Club’s Inner Circle also appear as the main antagonists of the second season of the television series The Gifted led by a character named Reeva Payge played by Grace Byers, and the Frost sisters played by Skyler Samuels.

In creating the Hellfire Club, Uncanny X-Men writer Chris Claremont and artist/co-writer John Byrne drew heavily upon a 1966 episode of the British spy series The Avengers entitled "A Touch of Brimstone". In the episode, agents John Steed and Emma Peel attempt to infiltrate a secret society named after the Hellfire Club of the 18th century, whose members of the "Inner Circle" wear period costumes. Peel's guise as "the Queen of Sin", dressed in a black leather corset, would be the model for the Club's Queens, and her first name borrowed for White Queen Emma Frost. The leader of the episode's club was played by actor Peter Wyngarde, best known for his role as Jason King, forming the basis for Mastermind's new "Jason Wyngarde" identity.

Claremont and Byrne similarly drew the names and faces of the other Hellfire Club members from famous actors: Sebastian Shaw was based on actor Robert Shaw, Harry Leland on Orson Welles (who acted as Harry Lime in The Third Man and whose film Citizen Kane featured a reporter named Jed Leland), and Donald Pierce was based on Donald Sutherland (the surname alluding to his Hawkeye Pierce character from M*A*S*H).

Later writers would add references to The Avengers: Sir Patrick and Lady Diana, from the Philadelphia branch of the 1780s, are named after actors Patrick Macnee (John Steed) and Diana Rigg (Emma Peel); conversely, the Black Queen of the London branch was revealed to be named Ms. Emma Steed.

The Hellfire Club counts among its members the most famous, wealthy, and influential members of society. Membership is passed on to descendants, and can also be earned through wealth or influence. While many accept the invitation simply for the pleasures that the Club offers, others seek wealth and influence. In fact, the purpose of the Hellfire Club is to obtain and exert power through politics and economic influence instead of outward conquest and domination. Since its foundation, the Hellfire Club has been involved in wars and assassinations to further the agendas of the Club's most powerful members.

The Club has branches in New York City, London, Hong Kong, Paris, and Buenos Aires; the various branches are all overseen by the Lord Imperial (a position long-held by Sir Gordon Phillips). Sebastian Shaw, the Black Bishop, began securing allies within the Club, meeting Harry Leland, Emma Frost, and Donald Pierce, as well as his loyal assistant, Tessa. Buckman, no longer having a use for the dangerously-ambitious Shaw, ordered a Sentinel attack on Shaw and his allies, resulting in the death of Shaw's lover, Lourdes Chantel. That night, Shaw and Emma Frost purge the entire Council of the Chosen, remaking it as the Lords Cardinal and appointing themselves Black King and White Queen.