"Only Girl (In the World)" is a song by Barbadian singer Rihanna from her fifth album, Loud (2010). Serving as the album's lead single, it was released on September 10, 2010. Crystal Johnson wrote the song in collaboration with producers Stargate and Sandy Vee. Rihanna contacted Stargate before Loud's production and asked them to create lively, uptempo music. "Only Girl (In the World)" was the first song composed for the album, and the singer decided to include it on the track list before she recorded her vocals. Backed by strong bass and synthesizer, it is a dance-pop and Eurodance song that has an electronic composition. Its lyrics describe Rihanna demanding physical attention from her lover.

Robyn Rihanna Fenty is a Barbadian singer, businesswoman, and actress, one of the most prominent recording artists of the 21st century. Rihanna signed with Def Jam Recordings in 2005 and found mainstream recognition following the release of her first two studio albums, Music of the Sun (2005) and A Girl Like Me (2006). Both influenced by Caribbean music, the albums quickly earned commercial success and peaked within the top ten on the US Billboard 200 chart. Her third album, Good Girl Gone Bad (2007), incorporated elements of dance-pop, and established her status as a prominent music industry icon. Its lead single "Umbrella" peaked atop the US Billboard Hot 100, won her first Grammy Award from three nominations, and remains one of the best-selling singles of all time.