Juno MacGuff
The titular Juno MacGuff is the film’s protagonist. She’s an outspoken, witty sixteen-year-old with a clear rebellious streak. She can come off as abrasive because of her sarcasm, but she can also be quite charming and her sardonic wit is often clearheaded and refreshing. Her gruff, tomboyish exterior belies an emotional, sensitive side that she keeps hidden as she can be easily overwhelmed by emotions. She is also prone to making rash decisions without thinking about the consequences of her actions. When she impulsively decides to have sex with longtime crush and childhood friend Paulie Bleeker, Juno ends up pregnant. She initially considers having an abortion, but soon has a change of heart and decides to keep her child but give her up for adoption instead. The film chronicles the emotional roller coaster ride of a 9-month pregnancy, which ends up being a journey of self-discovery.
Paulie Bleeker
The father of Juno's child, as well as Juno's best friend and longtime admirer, Paulie is a sensitive, gentle, genuinely caring, but timid soul. Like Juno, he too is a deeply emotional person, but unlike the blunt and opinionated Juno, Paulie is quiet and introspective, often keeping to himself as he sorts out his emotions. Upon discovering that Juno is pregnant, he withdraws in fear and confusion. Later, he shows up to her pregnancy and is by her side after she gives birth. His only vice is orange Tic-Tacs.
Vanessa Loring
The prospective adoptive mother that Juno has selected for her unborn child. Vanessa is the wife of Mark Loring, a frustrated rock musician and current ad jingle composer. She is portrayed as a generally ambitious, domineering yuppie-type who has clear priorities and high standards. Having gone through many years of disappointment trying to have a child, Vanessa is eager to have a baby and to be a mother. Vanessa's type-A personality and obsessive baby-planning drives a wedge in her relationship with Mark, which ultimately culminates in their divorce. Despite the divorce, Juno still gives her baby over to Vanessa to raise on her own.
Mark Loring
Vanessa's husband and the prospective adoptive father of Juno's child, he has a taste for loud punk rock and horror films that Juno also shares. Mark works from their home creating commercial jingles, but secretly longs for his glory days as a rock musician. In fact he has a room that Vanessa has designated as a shrine of sorts to his past, decked out with keepsakes and musical instruments. On the surface, Mark projects a cool and laid-back character—the polar opposite of his uptight wife—but after getting to know Juno better the façade of cool fades away to reveal his less mature impulses to stay in his punk rock past. Indeed, the last thing he wants to be is a father, and he even intimates that he wants to start an affair with the underage Juno, which disturbs her greatly. Mark is likable and charming, but suffers from a Peter Pan complex, and is dishonest to his wife about his desires.
Mac MacGuff
Juno's father is a middle-aged, bald, mustachioed man who can come off as intimidating because of his gruff demeanor, quick, sarcastic wit and blue-collar, no-nonsense attitude. His gruff exterior however is just that, a gruff exterior. He shows tremendous restraint with Juno, especially once she reveals that she is pregnant and that Paulie Bleeker is the father. Mac is genuinely warm towards his daughter and is honest to say that he doesn't quite have a clear-cut answer for her situation but he does advise care and restraint for any decision she decides to take regarding her pregnancy. His daughter’s pregnancy serves to grow and deepen the father-daughter relationship and, despite his shortcomings in his relationship with his ex-wife, he tries to offer Juno sound advice on finding lasting love.
Bren MacGuff
Mac’s second wife, stepmother to Juno, and biological mother of Juno’s younger sister, the curiously named Liberty Bell. Bren is the yin to Mac and Juno’s yang. Her relationship with her stepdaughter is cordial enough but still emotionally distant, more due to the awkwardness of their familial composition than an unwillingness to get to know her. This all changes though once word of Juno’s pregnancy gets out. Bren is fiercely caring and protective during Juno's pregnancy, and the hardship brings the stepmother and stepdaughter closer together. She comes to the fore as Juno’s much needed maternal figure and emotional support as her pregnancy progresses. Bren owns a nail salon and has an devotional fondness for dogs.
Leah
Juno's best friend who assists her in searching the help ads to find a suitable couple for her unborn child. Leah is a cheerleader and a popular girl, but she exhibits her fair share of quirkiness throughout the film. She has a thing for older men, which has led her into deep flirtations (and perhaps an affair) with her geometry teacher. She is loyal to Juno and helps her get through the pregnancy with a smile on her face.
Mrs. Bleeker
Paulie's mom, who doesn't approve of Juno, because of her quirky, punk-y demeanor, and eventually, because of her pregnancy. Juno and Paulie never tell her that Paulie is the father, and Juno maintains an irreverent dislike of Mrs. Bleeker, characterizing her as "a Hobbit...you know, the fat one, that was in the Goonies."
Su-Chin
Juno's classmate, who is the sole protestor outside the abortion clinic. She tells Juno that her unborn child has fingernails, which changes Juno's mind about getting an abortion.
