The sisters Fiordiligi and Dorabella are engaged to two young men, Guglielmo and Ferrando, respectively. The men have an older friend, Don Alfonso, who bets that he can get their sweethearts to fall in love with someone else. Ferrando and Guglielmo take him up on his wager, agreeing to do whatever he tells them. Don Alfonso enlists the help of Despina, the women’s maid, who is just as worldly-wise as he is. The men enter and tell their sweethearts they have joined the army and must leave. After a tearful farewell, in which everyone promises to be faithful, the men return, disguised as dashing “Albanians,” and proceed to court each other’s fiancée. The women at first reject them, prompting them to fake their suicides. Despina, disguised as a doctor, “cures” them and the women begin to show some interest in their exotic admirers.

Urged on by Despina, Fiordiligi and Dorabella decide that a little flirtation with the Albanians would be permissible. Guglielmo (still in disguise) renews his seduction of Dorabella and eventually succeeds in getting her to proclaim her love for him. Ferrando redoubles his efforts with Fiordiligi and she eventually succumbs to his charms. Don Alfonso arranges a double wedding, with Despina in disguise as the notary. Just after the women have signed the marriage contract, a military march is heard off-stage, representing the return of their sweethearts’ army regiment. The “Albanians” flee, soon to return as Ferrando and Guglielmo. The men seem shocked when they discover that their fiancées were about to marry two others. Eventually they admit the deception they’ve played on Fiordiligi and Dorabella, as do their co-conspirators Despina and Don Alfonso. The young couples acknowledge that they have learned an important lesson in understanding and forgiveness.