"Waking Up in Vegas" is a song by American singer Katy Perry, released as the fourth and final single from her second studio album, One of the Boys (2008). Perry wrote the song with Desmond Child and Andreas Carlsson, and Greg Wells produced it, who is also credited for playing all the instruments on the song. It was officially released to US radio stations on April 21, 2009. "Waking Up in Vegas" is a pop rock track about an underage couple getting drunk and blowing their money in Las Vegas, paying homage to the phrase "What happens in Vegas, stays in Vegas."