| Director | Ari Sandel |
|---|---|
| Genre | comedy film, teen film |
| Runtime | 101 min |
| Country | United States |
| Budget | $8.5 million |
| Box office | $43.7 million |
Bianca is enjoying her senior year of high school in the suburbs of Atlanta with her two best friends, Jess and Casey, who are both significantly more popular than her. Her neighbor is Wesley, the captain of the football team, who was her childhood friend.
Bianca reluctantly attends a party hosted by mean girl Madison, Wesley's "on-again, off-again" girlfriend, with hopes of talking to her guitar-playing crush Toby. At the party, Wesley casually brings to Bianca's awareness that she is the "DUFF" of her friend group—an acronym which stands for Designated Ugly Fat Friend. He explains that the DUFF does not necessarily have to be ugly or fat, it is merely the person in a social group who is less popular, and therefore more accessible, than the others in the group. Bianca is insulted and devastated, but she soon realizes Wesley is right: the students in her high school are only interested in her as a way to get to Jess and Casey.
She takes her anger out on Jess and Casey and "unfriends" them on social media and in person. She later overhears Wesley's science teacher Mr. Fillmore telling Wesley that unless he passes the midterm, he is off the football team, which could cost him his football scholarship. Desperate to up her social standing and go on a date with her crush, Bianca strikes a deal with Wesley: she will help him pass his class if he helps her socially. The two have a fun time at the mall, attempting a makeover by buying new clothes.
Secretly, Madison's henchgirl records Bianca embarrassingly playing around in her new clothes and pretending that a mannequin is Toby. Madison posts the video online to embarrass Bianca because she has become possessive of Wesley and jealous of Bianca's relationship with him. Wesley suggests Bianca just "own" the video and be upfront with Toby, talking directly to him and asking him out. She takes the advice and, to her surprise, he accepts. Bianca takes Wesley to her favorite spot in the forest, her "think rock", to get him away from the constant arguing between his parents, and to help him cope with a possible divorce. They kiss, but joke about it, and pretend it didn't mean anything.
Bianca and Toby have a date at his house, where she finds herself thinking about Wesley but tries to brush it off. By the end of the date, she discovers that Toby has been "DUFFing" her; that is, spending time with her in order to connect with Jess and Casey. She confronts him as the shallow and superficial person he has revealed himself to be, and leaves in tears. While looking for Wesley, to talk with him about the date, she finds him at the thinking rock kissing Madison.
Furious with both boys, Bianca reunites with her girl friends, who were actually genuine all along. They, along with her understanding mother, Dottie, convince her to go to the homecoming dance with them in a dress they create together which incorporates elements of her previous wardrobe, such as her plaid flannel shirts. At the dance, Bianca uses Wesley's advice to be upfront, and tells him that she likes him. However, he regrettably informs her that he is back with Madison, who approaches the two of them and begins to hurl insults at Bianca.
Bianca delivers her final speech to Madison, finally confronting her and proclaiming that everybody is a DUFF because there is always someone "better", and they should be true to their own identity. Additionally, Madison's bullying is just a reflection of her own insecurities about herself. When Madison is crowned homecoming queen and Wesley king, he hesitates before rejecting the title, instead choosing to kiss Bianca in front of the whole school.
Bianca's article about homecoming and her experience is a hit with the students. Bianca is accepted to Northwestern University while Wesley attends Ohio State. They go out for dinner as a couple.