Candide is the most widely read of Voltaire's many works, and it is considered one of the great achievements of Western literature. However, Candide is not necessarily considered a true "classic". According to Bottiglia, "The physical size of Candide, as well as Voltaire's attitude toward his fiction, precludes the achievement of artistic dimension through plenitude, autonomous '3D' vitality, emotional resonance, or poetic exaltation. Candide, then, cannot in quantity or quality, measure up to the supreme classics." Bottiglia instead calls it a miniature classic, though others are more forgiving of its size. As the only work of Voltaire which has remained popular up to the present day, Candide is listed in Harold Bloom's The Western Canon: The Books and School of the Ages. It is included in the Encyclopædia Britannica collection Great Books of the Western World. Candide has influenced modern writers of black humour such as Céline, Joseph Heller, John Barth, Thomas Pynchon, Kurt Vonnegut, and Terry Southern. Its parody and picaresque methods have become favourites of black humorists.
Charles Brockden Brown, an early American novelist, may have been directly affected by Voltaire, whose work he knew well. Mark Kamrath, professor of English, describes the strength of the connection between Candide and Edgar Huntly; or, Memoirs of a Sleep-Walker (1799): "An unusually large number of parallels...crop up in the two novels, particularly in terms of characters and plot." For instance, the protagonists of both novels are romantically involved with a recently orphaned young woman. Furthermore, in both works the brothers of the female lovers are Jesuits, and each is murdered (although under different circumstances). Some twentieth-century novels that may have been influenced by Candide are dystopian science-fiction works. Armand Mattelart, a French critic, sees Candide in Aldous Huxley's Brave New World, George Orwell's Nineteen Eighty-Four and Yevgeny Zamyatin's We, three canonical works of the genre. Specifically, Mattelart writes that in each of these works, there exist references to Candide's popularisation of the phrase "the best of all possible worlds". He cites as evidence, for example, that the French version of Brave New World was entitled Le Meilleur des mondes (lit. "The best of worlds").
Readers of Candide often compare it with certain works of the modern genre the Theatre of the Absurd. Haydn Mason, a Voltaire scholar, sees in Candide a few similarities to this brand of literature. For instance, he notes commonalities of Candide and Waiting for Godot (1952). In both of these works, and in a similar manner, friendship provides emotional support for characters when they are confronted with harshness of their existences. However, Mason qualifies, "the conte must not be seen as a forerunner of the 'absurd' in modern fiction. Candide's world has many ridiculous and meaningless elements, but human beings are not totally deprived of the ability to make sense out of it." John Pilling, biographer of Beckett, does state that Candide was an early and powerful influence on Beckett's thinking. Rosa Luxemburg, in the aftermath of the First World War, remarked upon re-reading Candide: "Before the war, I would have thought this wicked compilation of all human misery a caricature. Now it strikes me as altogether realistic."
The American alternative rock band Bloodhound Gang refer to Candide in their song "Take the Long Way Home", from the American edition of their 1999 album Hooray for Boobies.
In 1760, one year after Voltaire published Candide, a sequel was published with the name Candide, ou l'optimisme, seconde partie. This work is attributed both to Thorel de Campigneulles, a writer unknown today, and Henri Joseph Du Laurens, who is suspected of having habitually plagiarised Voltaire. The story continues in this sequel with Candide having new adventures in the Ottoman Empire, Persia, and Denmark. Part II has potential use in studies of the popular and literary receptions of Candide, but is almost certainly apocryphal. In total, by the year 1803, at least ten imitations of Candide or continuations of its story were published by authors other than Voltaire.
Candide was adapted for the radio anthology program On Stage in 1953. Richard Chandlee wrote the script; Elliott Lewis, Cathy Lewis, Edgar Barrier, Byron Kane, Jack Kruschen, Howard McNear, Larry Thor, Martha Wentworth, and Ben Wright performed.
The operetta Candide was originally conceived by playwright Lillian Hellman, as a play with incidental music. Leonard Bernstein, the American composer and conductor who wrote the music, was so excited about the project that he convinced Hellman to do it as a "comic operetta". Many lyricists worked on the show, including James Agee, Dorothy Parker, John Latouche, Richard Wilbur, Leonard and Felicia Bernstein, and Hellman. Hershy Kay orchestrated all the pieces except for the overture, which Bernstein did himself. Candide first opened on Broadway as a musical on 1 December 1956. The premier production was directed by Tyrone Guthrie and conducted by Samuel Krachmalnick. While this production was a box office flop, the music was highly praised, and an original cast album was made. The album gradually became a cult hit, but Hellman's libretto was criticised as being too serious an adaptation of Voltaire's novel. Candide has been revised and reworked several times. The first New York revival, directed by Hal Prince, featured an entirely new libretto by Hugh Wheeler and additional lyrics by Stephen Sondheim. Bernstein revised the work again in 1987 with the collaboration of John Mauceri and John Wells. After Bernstein's death, further revised productions of the musical were performed in versions prepared by Trevor Nunn and John Caird in 1999, and Mary Zimmerman in 2010.
Candido, ovvero un sogno fatto in Sicilia (1977) or simply Candido is a book by Leonardo Sciascia. It was at least partly based on Voltaire's Candide, although the actual influence of Candide on Candido is a hotly debated topic. A number of theories on the matter have been proposed. Proponents of one say that Candido is very similar to Candide, only with a happy ending; supporters of another claim that Voltaire provided Sciascia with only a starting point from which to work, that the two books are quite distinct.
The BBC produced a television adaptation in 1973, with Ian Ogilvy as Candide, Emrys James as Dr. Pangloss, and Frank Finlay as Voltaire himself, acting as the narrator.
Nedim Gürsel wrote his 2001 novel Le voyage de Candide à Istanbul about a minor passage in Candide during which its protagonist meets Ahmed III, the deposed Turkish sultan. This chance meeting on a ship from Venice to Istanbul is the setting of Gürsel's book. Terry Southern, in writing his popular novel Candy with Mason Hoffenberg adapted Candide for a modern audience and changed the protagonist from male to female. Candy deals with the rejection of a sort of optimism which the author sees in women's magazines of the modern era; Candy also parodies pornography and popular psychology. This adaptation of Candide was itself adapted for the cinema by director Christian Marquand in 1968.
In addition to the above, Candide was made into a number of minor films and theatrical adaptations throughout the twentieth century. For a list of these, see Voltaire: Candide ou L'Optimisme et autres contes (1989) with preface and commentaries by Pierre Malandain.
In May 2009, a play called "Optimism", based on Candide opened at the CUB Malthouse Theatre in Melbourne. It followed the basic storyline of Candide, incorporating anachronisms, music and stand up comedy from comedian Frank Woodley. It toured Australia and played at the Edinburgh International Festival. In 2010, the Icelandic writer Óttar M. Norðfjörð published a rewriting and modernisation of Candide, entitled Örvitinn; eða hugsjónamaðurinn. In May 2019, a new theatrical adaptation of Candide by John Taflan and Krista D'Agostino entitled, "Candide, or, Optimism, or #blessed, or, a journey into pain and suffering and the demise of privileged innocence and--wait, how are middle schoolers going to do this?, or, Candide!," opened at Mudlark Theater in Evanston, IL. Using the book as a departure point, the production featured middle school-aged actors playing Candide and his friends alongside adult actors playing Pangloss, Martin, and the Old Woman.