Nevermind is the second studio album by the American rock band Nirvana, released on September 24, 1991, by DGC Records. It was Nirvana's first release on a major label and the first to feature drummer Dave Grohl. Produced by Butch Vig, Nevermind features a more polished, radio-friendly sound than the band's prior work. It was recorded at Sound City Studios in Van Nuys, California, and Smart Studios in Madison, Wisconsin in May and June 1991, and mastered that August at the Mastering Lab in Hollywood, California.

Written primarily by frontman Kurt Cobain, the album is noted for channeling a range of emotions, being noted as dark, humorous, and disturbing. Thematically, it includes anti-establishment views, anti-sexism, frustration, alienation, and troubled love inspired by Cobain's broken relationship with Bikini Kill's Tobi Vail. Contrary to the popular hedonistic themes of drugs and sex at the time, writers have observed that Nevermind re-invigorated sensitivity to mainstream rock. According to Cobain, the sound of the album was influenced by bands such as Pixies, R.E.M., the Smithereens, and Melvins. Though the album is considered a cornerstone of the grunge genre, it is noted for its musical diversity, which includes acoustic ballads ("Polly" and "Something in the Way") and punk-inspired hard rock ("Territorial Pissings" and "Stay Away").

Nevermind became an unexpected critical and commercial success, hitting top 10 charts across the world. By January 1992, it reached number one on the US Billboard 200 and was selling approximately 300,000 copies a week. The lead single "Smells Like Teen Spirit" reached the top 10 of the US Billboard Hot 100 and went on to be inducted into the Grammy Hall of Fame. Its video was also heavily rotated on MTV. Three other successful singles were released: "Come as You Are", "Lithium", and "In Bloom". The album was voted the best album of the year in Pazz & Jop critics' poll, while "Smells Like Teen Spirit" also topped the single of the year and video of the year polls. The album also garnered the band three Grammy Award nominations in total across the 34th and 35th Grammy Awards, including Best Alternative Music Album.

Nevermind and its singles' success propelled Nirvana to being widely regarded as the biggest band of the 1990s, with Cobain being dubbed by critics as the "voice of his generation." The album brought grunge and alternative rock to a mainstream audience while ending the dominance of hair metal, drawing similarities to the early 1960s British Invasion of American popular music. It is also often credited with initiating a resurgence of interest in punk culture among teenagers and young adults of Generation X, becoming seminal to the counterculture of the decade. It has sold more than 30 million copies worldwide, making it one of the best-selling albums of all time. In March 1999, it was certified Diamond by the RIAA. Among the most acclaimed and influential albums in the history of music, Nevermind was added to the National Recording Registry in 2004 as "culturally, historically, or aesthetically significant", and is frequently ranked highly on lists of the greatest albums of all time. The album has since been reissued with alternate takes and live performances.