Quinn Fabray is a fictional character from the Fox musical comedy-drama series Glee. The character is portrayed by actress Dianna Agron, and has appeared in Glee from its pilot episode, first broadcast on May 19, 2009. Quinn was developed by Glee creators Ryan Murphy, Brad Falchuk and Ian Brennan. She begins the series as a popular girl who is Christian, head cheerleader and president of the celibacy club of the fictional William McKinley High School in Lima, Ohio, where the show is set, and joins Glee club during the second episode. Most of her storylines focus on her dealings with cheerleading coach Sue Sylvester (Jane Lynch), her plans to destroy the Glee club, and the aftermath of the discovery that she is pregnant, including telling her boyfriend Finn Hudson (Cory Monteith) that he is the father when it is really his best friend Noah Puckerman's (Mark Salling) baby. Her reign as queen bee of McKinley High ends when everyone discovers she's pregnant and she gets kicked off the Cheerios and stays in glee club. Her sidekick, Santana Lopez, becomes top dog soon after.

Agron was the last primary role to be cast, having won the role only days before the pilot began filming. She is described by Agron as Rachel's (Lea Michele) enemy, and "terrible, the meanest girl". The character's accidental pregnancy storyline has received mixed reviews from critics. Tim Stack for Entertainment Weekly deemed Quinn's pregnancy "a good dramatic twist", but hoped that it would not be a long-lasting storyline. However, reviews of her storyline became increasingly negative, though Agron was praised for her dramatic acting during the confrontation scene with Quinn's parents in "Ballad". Songs performed by Agron as Quinn have been released as singles, available for digital download, and also feature on the show's soundtrack albums.

Quinn is introduced as the head cheerleader at William McKinley High School. She is also president of the celibacy club, and the girlfriend of Finn Hudson (Cory Monteith), the quarterback of the football team. When Finn joins the school glee club, New Directions, Quinn fears she will lose him to the group's star, Rachel Berry (Lea Michele). Cheerleading coach Sue Sylvester (Jane Lynch) has Quinn and her friends Santana (Naya Rivera) and Brittany (Heather Morris) join the club to help her bring it down from the inside. Quinn discovers that she is pregnant, and tells Finn he is the father, despite the real father being his best friend Puck (Mark Salling). Puck tells Quinn that he will take care of her and the baby, but she rejects his offer, believing him to be irresponsible and a "Lima loser." Quinn decides to have the baby adopted, and agrees to give it to Terri (Jessalyn Gilsig), the wife of glee club director Will Schuester (Matthew Morrison), who is faking a pregnancy.

When Sue learns that Quinn is pregnant, she removes her from the cheerleading team. Quinn pressures Finn to find a job and help to pay her medical expenses. Puck tries to prove that he would be a good father, and offers her money that he steals from the glee club bake sale. Quinn refuses the money, but thanks him and apologizes for calling him a "Lima loser." When Quinn's parents learn of her pregnancy, they throw her out of their home and she moves in with Finn and his mother. Quinn begins to re-consider having the baby adopted, and gives Puck a chance to prove himself by helping her to babysit Terri's triplet nephews. Puck impresses her, but Quinn later learns that he spent the session sexting Santana. Puck states that would to be a good father, but he cannot remain in a commited relationship with Quinn if she doesn't have sex with him. Quinn returns to her original plan of giving the baby to Terri.

When the school yearbook photos are taken, Quinn attempts to rejoin the cheerleading team so she can be in their pictures. She ultimately decides she would rather be in the glee club, where she feels accepted. Rachel begins to suspect that Puck is the father of Quinn's baby, and tells Finn. When Finn confronts her, Quinn admits the truth, and Finn attacks Puck. Puck again offers to be with Quinn, but she turns him down and tells him she wants to be alone. She and Puck later enter into a relationship, however.

In the episode "Bad Reputation", Quinn makes a "Glist," showing how cool the Glee Club members are by how scandalous they act. When Will Schuester gives her a talk showing that even though her life isn't the same now that she isn't top dog anymore and is pregnant, he tells her she can make it better and so she learns her lesson.

In "Laryngitis" we discover that she's now living with Puck in his home. Also it is shown that she and Mercedes Jones (Amber Riley) have developed a good friendship and have respect for each other.

In "Theatricality", Puck suggests they call their unborn daughter Jackie Daniels, but Quinn coldly reminds him that she is giving the baby away so she doesn't have to look after the baby with him. Later, in an effort to prove he is serious about the situation, he sings the Kiss song "Beth" for Quinn, proposing they name the baby Beth. Quinn tearfully agrees and also allows him to be there when Beth is born.

In "Funk", Quinn wants a chance to "get funky" so she sings "It's a Man's Man's Man's World" and everybody comforts her. Later, she apologizes to Mercedes because she knows how it feels to be made fun of and laughed at, though Mercedes has dealt with it her whole life and Quinn has only had to for nine months. Mercedes observes that Quinn isn't angry but hurt. She also says Quinn needs a safe place where she can "dig up all that rage" and asks her to move into Mercedes' house.

In 'Journey' Quinn's mother returns to watch New Direction's performance at Regionals and tells her that she left Quinn's father because he was having an affair and she wants Quinn and the baby to move in with her. Quinn's water breaks and the Glee club takes her to give birth, with Mercedes, Puck and Quinn's mother in the delivery room with her. While watching Beth, she asks Puck if he loved her, and he replies he did, and still does. They share a smile and secret looks in Puck and Will's performance of "Over The Rainbow." Shelby Corcoran adopts Beth.

Following the episode "Hairography", Bobby Hankinson of the Houston Chronicle commented positively on Quinn's characterization, noting: "I love being able to see different sides of Dianna Agron. As Quinn, she started so one-dimensional and has grown so much ever since. I love that she can keep her Mean Girls edge while being heartbreakingly sad or as joyful as she was singing "Papa Don't Preach".

In an interview with Rolling Stone, creator and producer Ryan Murphy stated that "When we cast Dianna as Quinn, she ruined the part for me. She was supposed to be the Cybill Shepherd, Last Picture show, so to speak, but she humanized it. She can cry at the drop of a hat. So now her character has a conscience, a soul, and great vulnerability."

Songs performed by Agron as Quinn have been released as singles, available for digital download, also featuring on the soundtrack Glee: The Music, Volume 1. Of her centric performances, "I Say a Little Prayer" charted at 125 in the United Kingdom, "You Keep Me Hangin' On" charted at 166, and "Papa Don't Preach" charted at 81.