"Loca" is the lead single from Shakira's ninth studio album Sale el Sol. The song was released in both English and Spanish versions. It also received diamond certification in Colombia and Spain.

The song was written and produced by Shakira. It was re-interpreted from a merengue track by Dominican rapper El Cata, called "Loca por su tigre." This was the most explicit line in Shakira's song catalog. However, the lyrics do not translate well into English, as the meaning is not clear.

According to the lawsuit, Shakira's version of "Loca" was a copyright violation. In July 2012, Sony Corp., which distributed the song in the United States, filed a copyright infringement lawsuit against Ramon Arias Vasquez, the composer of the song. During the trial, songwriter Ramon Arias Vasquez claimed that his recording of the song was not a copy of the song, but rather a version inspired by a love triangle between a sister and two lovers. He provided a cassette tape with a recording from the mid-1990s. Despite these claims, a federal judge found that the song was plagiarized.

SonyATV Latin and SonyATV Discos are the two companies that distribute the song in the United States. After the trial, it was determined that the lyrics in the English version are not authentic and that it does not have any connections to the original song.

Loca was a big hit for Shakira in Latin America, Africa and Asia. She reached the top of the Latin Billboard charts with it. The song became Shakira's ninth top 40 hit, and was moderately successful in the United States.