"Oops!... I Did It Again" is a pop song by American singer Britney Spears, released on April 11, 2000, as the lead single from her second studio album of the same name. The song was written and produced by Max Martin and Rami Yacoub. It features a catchy chorus and a spoken dialogue bridge referencing the 1997 film Titanic. The song received positive reviews from critics and was commercially successful, topping the charts in over 20 countries and reaching number nine on the US Billboard Hot 100. The music video depicts Britney in a red bodysuit dancing on Mars, and it received several MTV Video Music Award nominations. Britney has performed the song on multiple tours and special events throughout her career.

The song's lyrics revolve around a playful warning to a lover about not being so easily fooled by feelings of love, summarizing the theme with the refrain "Oops, I did it again, I played with your heart, got lost in the game." The album "Oops!... I Did It Again" was also a major commercial success, with over 20 million copies sold worldwide.