Nimrod stylized as nimrod is the fifth studio album by the American punk rock band Green Day, released on October 14, 1997 through Reprise Records. The group began work on the album in the wake of their cancellation of a European tour after the release of Insomniac (1995). Recorded at Conway Studios in Los Angeles, the album was written with the intent of creating a set of stand-alone songs as opposed to a cohesive album.

The album peaked at number ten on the Billboard U.S. charts and was certified double platinum by the Recording Industry Association of America (RIAA). The record was also certified triple platinum in Australia and double platinum in Canada. Upon release, Nimrod received generally positive reviews from critics, who praised Armstrong's songwriting. The album yielded the acoustic hit "Good Riddance (Time of Your Life)", which appeared in numerous pop culture events, including the series finale of the sitcom Seinfeld in 1998. To promote the album, Green Day embarked on an extensive touring schedule.

Retrospectively, Nimrod is noted for its musical diversity and experimentation. It contains elements of folk, surf rock, and ska; the lyrical themes discussed on the record include maturity, personal reflection, and fatherhood. Nimrod has sold over 10 million copies worldwide.