Juno MacGuff is sixteen years-old who after a one-time sexual encounter with her best friend Paulie, learns that she's pregnant. Juno and Paulie like each other, but not enough to start a family, complete with a child. Paulie leaves all the decisions about the baby to Juno. Initially she decides to have an abortion, but can't go through with it. So she decides to have the baby and give it up for adoption. The next step is to find prospective parents for the yet unborn child. In the Pennysaver ad section, Juno finds Mark and Vanessa Loring, a yuppie couple living in the suburbs. Juno likes the Lorings and of her own choosing, she enters into a closed adoption contract with the Lorings. During the second and third trimesters of Juno's pregnancy, which she treats with care but detachment, her relationships with her family, with Paulie, and with the Lorings develop.