This film began with a girl names Juno, reminding the moment when she and her bestfriend Paulie, were making love. Then she goes to the grocery store, buying pregnancy test. And it turn out positive. Her first response is trying to commit suicide, but then she just can’t do it. Then Juno call her friend, Leah, to tell her pregnancy. Leah is surprised, but suggesting Juno to do an abortion.
The next day, Juno is telling Paulie that she’s pregnant. Paulie seems surprised and confused, but he give the decision to Juno for everything she will do with her pregnancy.
So Juno has been pretty sure for doing an abortion, and she goes to the Woman Now to do that. But when she gets there, Juno meet her friends that doing a campaign that babies have the right to life and telling Juno that babies have fingernails. That’s when Juno decide to cancel an abortion, she wants to keep the pregnancy until she gives birth and make someone adopt the baby.
With Leah’s help, they seeking for a couple that want to adopt a baby. Then after finding the perfect couple, Juno must tell her parents about her pregnancy. Surprisingly, her parents handle it very well and support Juno, though her father is surprised.
Along with her father, Juno meets the couple (Mark and Vanessa) that want to adopt her baby. They are a rich couple that has been waiting so long for having baby. The couple offer an open adaption where Juno can get the updates about her baby. But Juno wants a closed adoption, she just want to give the baby right after when she has giving birth.
Then Juno’s stomach is getting bigger. She get an ultrasound examination and get her baby photographed. She can’t wait to show the baby’s picture to Vanessa and Mark, so Juno drive right through their house. When Jono comes there, Mark is alone in the house. They have a chit chat and it turns out that they have the same hobby and interest and feel connected. Right after Juno come back to her home, her step Mother, Bren, asking where she was go. And Juno tell the truth. Bren is forbidding Juno to come visiting Mark when he is alone, a married man has his own boundary. But Juno is ignoring it.
Juno comes to Paulie’s house and tell him that she already got a couple to adopt the baby, and ask if he’s cool with it. Paulie seems find to that option and even he said he want to be together with Juno again when everything had settled down. But Juno refuse him and ask Pauliee to date Katrina.
Juno is calling Mark just to say hi and talking about small things. Then Juno heard that Paulie is going to Prom with Katrina. So Juno talks to Pauliee and she seems angry. When Paulie say she was angry, Juno refuse to admit it then she just spill out her feeling about her pregnancy and blame Pauliee. Pauliee say that Juno doesn’t have the right to angry for him going with Katrina, because Juno has breaks Pauliee’s heart for refusing him.
Then in a mad feeling, Juno go to Mark’s house. They chatting about the movie, comics and music that they both love. It makes Mark realize his feeling to Juno, and he tells Juno that he wants to divorce Vanessa and he isn’t ready to have a baby. It makes Juno cry. Then vaness cames home, and Mark tell her that he doesn’t ready to have a baby and want to have a divorce. Hearing that makes Juno shock and leave them. In her way home, juno cry hard. But she remember how Vanessa really wants a baby, so she drive back to Vanessa’s house and give her a note.
Then Juno get to home and telling her father that she doesn’t have a faith anymore in love. But her father encourage her and tell her that someone that still loves you no matter how bad your condition, he worth to be live with. It makes Juno realize that Paulie is the person that meets her father words. So she came to Pauliee and say that she loves him, and it makes Pauliee so happy because he love her too.
Not long after that, Juno feels the birth contraction. Her family hasten to bring her to the hospital. Juno doesn’t tell Paulie that she is giving birth because Paulie is having a race today. But after the race, Pauliee realize that Juno wasn’t there, so it must be that she giving birth. Pauliee run into the hospital then found Juno exhausted after giving birth. Then he hug Juno tight. They both decide not to see the baby. After that Vanessa is getting the baby that she wanted all along.
The story ends at summer, when Juno had a normal life as a student again. And now she’s going out with Pauliee. They both realize that they love each other.