Glee (stylized as glee) is an American musical comedy-drama television series that aired on Fox in the United States from May 19, 2009, to March 20, 2015. It centers on the New Directions, a glee club at the fictional William McKinley High School, that is located in the American state of Ohio, which competes as a show choir while its disparate members deal with social issues, especially regarding sexuality, race, family, teen relationships and teamwork.

The initial twelve-member cast included Matthew Morrison as club director and Spanish teacher Will Schuester, Jane Lynch as scheming cheerleading coach Sue Sylvester, Jayma Mays as the guidance counselor Emma Pillsbury, who has OCD, Jessalyn Gilsig as Will's wife Terri, and the eight original club members, including Dianna Agron as Quinn Fabray, a popular cheerleader who experiences a teenage pregnancy; Chris Colfer as Kurt Hummel, an effeminate, gay boy who feels conflicted by his sexuality and is bullied at school; Kevin McHale as Artie Abrams, who lives with a physical disability; Lea Michele as Rachel Berry, driven by her dreams of becoming a Broadway theatre star and the glee club's most obvious star singer; Cory Monteith as Finn Hudson, the school's star quarterback who sometimes appears not to be very smart; Amber Riley as Mercedes Jones, a black girl who endeavors to be recognized for her talents and dreams of being a vocal diva; Mark Salling as Noah Puckerman, a teenage delinquent in need of direction; and Jenna Ushkowitz as Tina Cohen-Chang, a shy, Korean-American goth who longs to be popular and sometimes experiences racism. The main cast was altered throughout the series, including the addition of Naya Rivera as Santana Lopez, a sardonic and cynical Latina cheerleader experiencing deep conflict over her sexuality, Harry Shum Jr. as Mike Chang, a soft-spoken Chinese-American dancer whose parents do not support his dreams, and Heather Morris as Brittany Pierce, a ditzy cheerleader who is secretly a math prodigy and comes to realize she is bisexual.

The series was created by Ryan Murphy, Brad Falchuk, and Ian Brennan, the latter of whom first conceived of Glee as a film. The three wrote all of the show's episodes for the first two seasons, and Murphy and Falchuk initially served as the show's main directors. The pilot episode was broadcast on May 19, 2009, and the first season aired from September 9, 2009, to June 8, 2010. Subsequent seasons aired from September through May. The sixth and final season aired from January to March 2015. Glee features on-screen performance-based musical numbers that were selected by Murphy, who aimed to maintain a balance between show tunes and chart hits, and produced by Adam Anders and Peer Åström. Songs covered in the show were released through the iTunes Store during the week of broadcast, and a series of Glee albums have been released by Columbia Records. The music of Glee has been a commercial success, with over 36 million digital single sales and eleven million album sales worldwide through October 2011. The series' merchandise also includes DVD and Blu-ray releases, an iPad application, and karaoke games for the Wii home videogame console. There were live concert tours by the show's cast after the first and second seasons completed shooting; a concert film based on the 2011 tour, Glee: The 3D Concert Movie, was produced by Murphy and Fox and directed by Kevin Tancharoen.

During its first season, Glee received generally favorable reviews from critics, with Metacritic's weighted average of 77 out of 100 based on 18 critical reviews. Glee has won many accolades. The season was nominated for 19 Emmy Awards, four Golden Globe Awards, six Satellite Awards and 57 other awards, with wins including the 2010 Golden Globe Award for Best Television Series – Musical or Comedy, and Emmy awards for Jane Lynch, guest-star Neil Patrick Harris and Murphy's direction of the pilot episode. In 2011, the show once again won the Golden Globe for Best Television Series, and Jane Lynch and Chris Colfer won Golden Globes for Best Supporting Actress and Best Supporting Actor respectively, and Gwyneth Paltrow won the Emmy for Outstanding Guest Actress in a Comedy Series. The show was also chosen by Fox to fill the coveted time slot that followed the network's coverage of Super Bowl XLV in 2011.

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