Madame Pernelle is hastily leaving her son’s house, incensed by some of her family member’s treatment of their houseguest Tartuffe. While others try to argue that Tartuffe is a con man, who uses religion as a shield for his true nature, Madame Pernelle berates them, claiming that Tartuffe is a godly clergyman who is offended by sin. When everyone again tries to reason with her, Madame Pernelle exits, offended.
After she leaves, the family confers, discussing the fate of Orgon, the head of the family who deeply esteems Tartuffe. They are worried that Tartuffe has Orgon completely under his spell. Orgon’s son Damis and Dorine (the family’s loyal maid) ask Cleante, Orgon’s brother-in-law, to ask Orgon about the status of Mariane’s upcoming nuptials to Valere. They are worried that Orgon might be delaying the wedding. When Cleante asks Orgon about his plans for the wedding, Orgon tries to evade the conversation, and instead keeps extolling the many virtues of Tartuffe. Cleante leaves, exasperated after his unsuccessful discussion with Orgon.
Orgon finds Mariane and tells her that he has new nuptial plans for her: she will be marrying Tartuffe, instead of Valere. Mariane is too shocked to say anything, and Orgon, leaves the room, satisfied.
Dorine reprimands Mariane for not refusing to marry Tartuffe. Mariane’s love, Valere, arrives and is shocked to find that Mariane is not planning to refuse her father’s wishes. The two briefly argue; Dorine finally interrupts and reconciles the lovers. Dorine promises to help expose Tartuffe and, in so doing, ensure that Mariane is able to marry the man she truly loves.
Dorine devises a way to get Tartuffe and Elmire, Orgon’s wife, alone. She believes that Tartuffe has feelings for Elmire, and that Elmire might be able to persuade Tartuffe to call off the engagement with Mariane. Instead, Tartuffe confesses his love for Elmire, and tries to seduce her. Damis, who has been hiding in the room, bursts forth