It was first performed at the Opéra Garnier in Paris on 16 March 1894, starring the American soprano Sibyl Sanderson, for whom Massenet had written the title role.

The work was first performed in Italy at the Teatro Lirico Internazionale in Milan on 17 October 1903 with Lina Cavalieri in the title role and Francesco Maria Bonini as Athanaël.

Thaïs takes place in Egypt under the rule of the Roman Empire, where a Cenobite monk, Athanaël, attempts to convert Thaïs, an Alexandrian courtesan and devotee of Venus, to Christianity, but discovers too late that his obsession with her is rooted in lust; while the courtesan's true purity of heart is revealed, so is the religious man's baser nature.

Its famous Méditation, the entr'acte for violin and orchestra played between the scenes of act 2, is an oft-performed concert music piece; it has been arranged for many different instruments.

The role of Thaïs, similar to another Massenet heroine also written for Sibyl Sanderson, Esclarmonde, is notoriously difficult to sing and is reserved for only the most gifted of performers.

Modern interpreters have included Carol Neblett, Anna Moffo, Beverly Sills, Leontyne Price, Renée Fleming, and Elizabeth Futral.

In the 1894 version the end of act 1, the supposed striptease of Thaïs (which caused a great scandal on the first night due to a mishap with Sibyl Sanderson's costume) is a long symphonic interlude "L'amours d'Aphrodite" that leads without a break into act 2 and the scene with the mirror aria "Dis-moi que je suis belle".

There is a strangely experimental middle section, that is in an amorphous 5/4 time signature (unusual for Massenet) with a sultry whole-tone feel.

In the 1898 revision, there is an extended ballet sequence in act 2 for Nicias' followers, including the little vocal intermezzo for La charmeuse.

In it Athanaël is tormented by spirit voices, La perdition, L'étoile de la rédemption (star of redemption), Les sphinges (Sphinxes), Âmes perdues (lost souls) and Esprits de L'abîme (spirits of the abyss) culminating in an orgiastic black sabbath.

Athanaël, the most rigorous ascetic of them all, enters and confesses to the senior monk, Palémon, that he has lately been disturbed by visions of a courtesan and priestess of Venus named Thaïs, whom he had seen many years ago in his native city of Alexandria.

Believing these visions to be a sign from God, he resolves, against Palémon's advice, to return to Alexandria, convert Thaïs to Christianity, and persuade her to enter a convent.

Scene 1 Exhausted after the feast, Thaïs expresses dissatisfaction with her empty life and muses on the fact that one day, old age will destroy her beauty.

Although Nicias is astonished at Thaïs' decision to leave, he respects it and throws handfuls of money to distract the crowd.

They reach a spring, where Athanaël begins to feel pity rather than disgust for her, and they share a few moments of idyllic, platonic companionship as they rest.