The play is set in Sweden in the 1880s on Midsummer’s Eve; all of the action takes place in a kitchen in the Count’s home. Kristin, the cook, is preparing something for the Count’s daughter, Miss Julie, for the holiday. Jean, the valet, joins her and the two flirt and discuss their engagement. Jean is disdainful about Miss Julie’s “wild” behavior dancing with the servants. Miss Julie's own engagement has just ended, with the fiance apparently storming off and leaving her, and she has not been behaving appropriately since.
Miss Julie whirls into the kitchen and insists Jean dance with her, as all rank is laid aside for Midsummer. He clearly finds her attractive, but is reluctant to do so because of his status and his dedication to his Lordship. He gives in, and later returns to tell Kristin that Miss Julie danced with him too much.
Kristin falls asleep, and Miss Julie joins Jean in the kitchen. She is intrigued by the fact that he speaks French and asks about his life. She becomes flirtatious, playfully demanding he kiss her feet. He warns her that such behavior is dangerous because people will talk, but she does not care. She mentions a dream she frequently has of being high up in a tree and wanting to get down but not being able to, and he shares his own of lying under a tree and wanting to climb up but not being able to do so.
The sexual tension between them now palpable, Miss Julie and Jean have sex, but almost immediately regret it. Jean suggests they run away and start a hotel in Switzerland, but Miss Julie says that is not possible without money and her family does not have as much as it seems. She recounts her tumultuous childhood and how she was taught by her free-spirited, equality-loving mother to hate men.
Miss Julie wants Jean to tell her he loves her but he refuses to do so while they are still in the Count’s house. This makes Miss Julie despair, and Jean becomes increasingly frustrated with her. He condemns her for being a whore and transgressing social boundaries.
Kristin joins them and Miss Julie appeals to her as a woman, but Kristin is disdainful of her behavior. Jean thinks Kristin still needs to respect Miss Julie as her superior because that is the way rank and society work, but Kristin is unconvinced. She leaves to go to church, telling Miss Julie that she believes grace can save even the most lowly sinner because the Bible says the first can become last.
Miss Julie is intrigued by this, especially as it seems like there is no other option for her. She cannot stay, she cannot go, and Jean is doing nothing to help her. His Lordship comes home (though he does not appear onstage) and both Miss Julie and Jean are terrified that he will find out what has happened.
Miss Julie begs Jean to order her to kill herself, since she does not have enough strength to do it herself. He is frightened and does not want to, but succumbs and gives her his razor. She walks out the door with razor in hand, hoping she will find grace as Kristin suggested. It is implied she kills herself.
