Glee (stylized in all lowercase as glee) is an American jukebox musical comedy-drama television series created by Ryan Murphy, Brad Falchuk, and Ian Brennan for the Fox Broadcasting Company. Taking place at the fictional William McKinley High School in Lima, Ohio, the series focuses on the New Directions, a glee club competing in the show choir circuit, as its disparate members deal with social issues regarding sexuality, gender, race, family, relationships, and teamwork.

The initial twelve-member cast included Matthew Morrison as Will Schuester, Jane Lynch as Sue Sylvester, Jayma Mays as Emma Pillsbury, and Jessalyn Gilsig as Terri Schuester. The remaining cast portrayed students, with Dianna Agron as Quinn Fabray, Chris Colfer as Kurt Hummel, Kevin McHale as Artie Abrams, Lea Michele as Rachel Berry, Cory Monteith as Finn Hudson, Amber Riley as Mercedes Jones, Mark Salling as Noah Puckerman, and Jenna Ushkowitz as Tina Cohen-Chang. Later additions included Naya Rivera as Santana Lopez, Harry Shum Jr. as Mike Chang, Heather Morris as Brittany Pierce, Chord Overstreet as Sam Evans, Darren Criss as Blaine Anderson, Alex Newell as Unique Adams, Melissa Benoist as Marley Rose, and Becca Tobin as Kitty Wilde.

First conceived by Brennan as a feature film, Glee was primarily written by him, Murphy, and Falchuk in the first two seasons; Murphy and Falchuk also served as the series' initial directors. The pilot episode premiered on May 19, 2009, and the first season aired from September 9, 2009, to June 8, 2010. Subsequent seasons aired from September through May, while the sixth and final season aired from January to March 2015 with only 13 episodes. Glee features on-screen musical performances chosen by Murphy and produced by Adam Anders and Peer Åström, ranging from show tunes to chart hits. Songs covered in the series were released through the iTunes Store during the week of broadcast, and several Glee albums have been released by Columbia Records. The series' music has been commercially successful, with over 36 million digital single sales and 11 million album sales worldwide through October 2011. Other merchandise includes DVD and Blu-ray releases, an iPad application, and karaoke games for the Wii console. The cast embarked on live concert tours after filming the first and second seasons; a concert film based on the 2011 tour, produced by Murphy and directed by Kevin Tancharoen, had a limited theatrical release in August 2011.

Glee received generally favorable reviews from critics in its first season, while reception to the later five varied. Among its many accolades, it won six Primetime Emmy Awards (including acting wins for Lynch and guest stars Neil Patrick Harris and Gwyneth Paltrow, along with Murphy's direction of the pilot), four Golden Globe Awards (including two consecutive awards for Best Television Series – Musical or Comedy and acting wins for Jane Lynch and Chris Colfer), and the 2009 Screen Actors Guild Award for Outstanding Performance by an Ensemble in a Comedy Series. In 2011, Fox chose the show to fill the coveted time slot following the network's coverage of Super Bowl XLV.

In 2013, following Monteith's death and the airing of his tribute episode "The Quarterback", Murphy announced that the sixth season would be the series' last. After 121 episodes and over 729 music performances, Glee concluded on March 20, 2015.

The series centers on a show choir and glee club at the fictional William McKinley High School in Lima, Ohio. Spanish teacher Will Schuester (Matthew Morrison) takes over the glee club after former teacher Sandy Ryerson (Stephen Tobolowsky) is fired for inappropriate contact with a student, and attempts to restore the newly named "New Directions" to its former glory while tending to his developing feelings for his co-worker, guidance counselor Emma Pillsbury (Jayma Mays). Will must also defend the glee club's existence from scheming cheerleading coach Sue Sylvester (Jane Lynch) and at times, school Principal Principal Figgins (Iqbal Theba). The series gives focus to the lives of the eventual members of the New Directions: their romances, their love of singing and desire for popularity clashing with their membership in the low-status club, and the many vicissitudes that come with high school and teenhood.

The first season follows the New Directions competing for the first time on the show choir circuit, from their win at the Sectionals competition (episode 13) to their loss at Regionals (episode 22). Social issues explored in this season include sex, relationship problems, homosexuality, teenage pregnancy, disabilities, acceptance. Will Schuester's (Matthew Morrison) marital issues are also in the spotlight in the first season, as his then wife Terri Schuester (Jessalyn Gilsig), Will's high school sweetheart and manipulative wife, fakes a pregnancy to trap Will in their marriage. This storyline jumpstarts Will and Emma Pillsbury's (Jayma Mays) romantic storyline as they get together for the first time after Will and Terri's divorce. Terri and Will's storyline was very popular amongst fans and can be attributed to part of the shows quick success. The inaugural members of the New Directions include Rachel Berry (Lea Michele), an ambitious performer driven by her dreams of becoming a Broadway theatre star; Finn Hudson (Cory Monteith), the school's sometimes-slow-witted star quarterback; Artie Abrams (Kevin McHale), a boy with a physical disability; Kurt Hummel (Chris Colfer), an effeminate, openly gay boy; Mercedes Jones (Amber Riley), an aspiring vocal diva whose talents go unrecognized; Tina Cohen-Chang (Jenna Ushkowitz), a shy goth longing to be popular; Noah "Puck" Puckerman (Mark Salling), a delinquent in need of direction; and Quinn Fabray (Dianna Agron), a popular cheerleader who experiences a teenage pregnancy and was asked to sell her baby to Terri in hopes of successfully tricking Will into thinking Terri actually had his baby.

The second season follows the club through wins at Sectionals (episode 9) and Regionals (episode 16) before losing at the Nationals competition in New York City (episode 22), while dealing with relationship problems, religion, homophobia, bullying, rumors, teenage drinking, and death. Club members promoted to the main cast this season include Santana Lopez (Naya Rivera), a snarky, cynical cheerleader struggling with her sexuality; Brittany S. Pierce (Heather Morris), a ditzy, promiscuous cheerleader who later dates Santana; and Kurt's father Burt Hummel (Mike O'Malley).