"Blurred Lines" is a single written and performed by American recording artists Robin Thicke, T.I. and Pharrell Williams (credited as "Pharrell"). Produced by Williams, the song was released as the lead single from Thicke's album of the same name on March 26, 2013 through Star Trak Recordings. Recorded in 2012, the song was primarily inspired by the Marvin Gaye song "Got to Give It Up", and was largely the work of Williams. However, Thicke clearly laid claim to writing credits on the track according to a Reuters article. The song became the subject of a bitter legal dispute with the family of Gaye and Bridgeport Music as to whether the song infringed copyrights to "Got to Give It Up". Thicke and Williams were found liable of copyright infringement by a federal jury in March 2015.

The song's music video was released in two versions, with one featuring models Emily Ratajkowski, Jessi M'Bengue, and Elle Evans being topless, while the other censored nudity. The uncut version of the video was at one time removed from YouTube for violating the site's terms of service regarding nudity; it was later restored, but with an age restriction. The song's lyrics and music video has also proved controversial with some groups, with claims that it is misogynistic and promotes date rape. This has led to the song being banned at universities and other institutions in the United Kingdom, and prompted a rebuttal from Thicke.

"Blurred Lines" was an immense success worldwide, peaking at number one in 20 countries. In the US, it was the longest running number one single of 2013. The song subsequently became one of the best-selling singles of all time, with sales of 14.8 million, simultaneously breaking the record for largest radio audience in history. The single was nominated for two Grammys at the 56th Annual Grammy Awards, including Record of the Year and Best Pop Duo/Group Performance. The song became the basis for numerous parodies and cover versions.