Sour (stylized in all caps) is the debut studio album by American singer-songwriter Olivia Rodrigo. It was released on May 21, 2021, via Geffen Records. The album was recorded in isolation during the COVID-19 lockdowns, with its production handled by Dan Nigro, who also co-wrote the album alongside Rodrigo. Originally planned as a debut EP, Sour was upgraded to a full-length album after the viral success of Rodrigo's debut single, "Drivers License".
Inspired by Rodrigo's favorite genres and singer-songwriters, Sour is primarily a pop and alt-pop record that spans from energetic pop punk songs to bedroom pop ballads. Its subject matter centers on adolescence, failed romance and heartache. She said the album explores her perils and discoveries as a 17-year-old, with its title referring to the "sour" emotions young women experience but are often criticized for, such as anger, jealousy and unhappiness. Sour received critical acclaim upon release; reviews regarded it a solid debut album, underscoring Rodrigo's musical versatility, honest lyrics, and Generation Z appeal.
Three singles preceded Sour's release, all of which reached the top 3 of the US Billboard Hot 100. The lead single, "Drivers License", topped the chart and propelled Rodrigo to mainstream prominence. It was followed by "Deja Vu", which reached number 3, and "Good 4 U", the album's second chart-topper. It made Rodrigo the first artist in history to debut their first two singles inside the top 10 of the Hot 100, and Sour the first debut album in history to spawn two number-one debuts on the chart. Additionally, "Traitor" reached number nine, marking the album's fourth top-ten Hot 100 entry. Sour opened atop the US Billboard 200 with the biggest first week of 2021, and reached number one in many other countries, such as Australia, Canada, Ireland, New Zealand, and the UK. It broke the global Spotify record for the biggest opening week for an album by a female artist.