"Oops!... I Did It Again" is a song recorded by American singer Britney Spears, from her second album of the same name. It was released on March 27, 2000, by Jive Records as the lead single from the album. It was written and produced by Max Martin and Rami Yacoub. Lyrically, the song refers to a female who views love as a game, and she decides to use that to her advantage by playing with her lover's emotions. Its bridge features a dialogue that references the 1997 film Titanic.

Upon its release, "Oops!... I Did It Again" received positive reviews from music critics, who noted similarities to Spears' debut single "...Baby One More Time". It was nominated for Best Female Pop Vocal Performance at the 43rd Annual Grammy Awards. Commercially, the song peaked at number nine on the US Billboard Hot 100. It topped the charts in at least 15 countries.

An accompanying music video was directed by Nigel Dick. It depicts Spears on Mars, where she addresses an astronaut who has fallen in love with her. She is dressed in a red bodysuit. It went on to receive three nominations at the 2000 MTV Video Music Awards. Spears has performed the song during her Oops!... I Did It Again Tour, Dream Within a Dream Tour, The Onyx Hotel Tour, and Britney: Piece of Me.