Oops!... I Did It Again is the second studio album by American singer Britney Spears. It was released on May 3, 2000, by Jive Records.

Following the tremendous commercial success of her debut studio album ...Baby One More Time (1999) and the completion of its accompanying concert tour of the same title, Spears began recording material for her second studio album in September 1999. Pressured to duplicate the success of ...Baby One More Time, she collaborated with a wide range of producers, including Max Martin, Rami Yacoub, Per Magnusson, David Kreuger, Kristian Lundin, Jake Schulze, Darkchild, and Robert John "Mutt" Lange for Oops!... I Did It Again. The final result was a pop, dance-pop and teen pop record exceedingly in the vein of ...Baby One More Time, but incorporating funk and R&B. The production, sonic quality, and Spears' vocal performance received critical acclaim upon the album's release.

Much like its predecessor, Oops!... I Did It Again became a massive commercial success, debuting atop the US Billboard 200, with first-week sales of 1.319 million copies, holding the record for the fastest-selling album by a female artist and the largest first-week sales for a female album for 15 years, until it was broken by Adele's 25 (2015), which sold over 3.38 million copies in its first week. In addition, Oops!... I Did It Again received a nomination for Best Pop Vocal Album at the 43rd Annual Grammy Awards (2001). It became Spears' second consecutive album to be certified diamond by the Recording Industry Association of America (RIAA), making Spears the youngest artist to have multiple diamond albums. With worldwide sales of over 20 million copies, it is one of the best-selling albums of all time.

Oops!... I Did It Again produced four singles. Its title track was a global commercial success, reaching number one in 15 countries and peaking at number nine on the US Billboard Hot 100. "Lucky" peaked within the top ten in 16 countries, but only at number 23 on the US Billboard Hot 100. "Stronger" peaked at number 11 on the US Billboard Hot 100 and became the best-selling single from the album. The final single "Don't Let Me Be the Last to Know" was moderately successful across Europe and failed to chart altogether in the United States. To promote the album, Spears performed on several television shows and award ceremonies, including a controversial performance at the 2000 MTV Video Music Awards, also hosting and performing for the first time on Saturday Night Live. Furthermore, she embarked on her third concert tour, entitled the Oops!... I Did It Again Tour (2000).