Lindsay or Lindsey () is an English surname and given name. The given name comes from the Scottish surname and clan name, which comes from the toponym Lindsey, which in turn comes from the Old English toponym Lindesege ("Island of Lind") for the city of Lincoln, in which Lind is the original Brittonic form of the name of Lincoln and island refers to Lincoln being an island in the surrounding fenland. Lindum Colonia was the Roman name of the settlement which is now the City of Lincoln in Lincolnshire. (Lindum Colonia was shortened in Old English to Lindocolina and then Lincylene.) Lindum was a Latinized form of a native Brittonic name which has been reconstructed as *Lindon, which means "pool" or "lake" (cf. the second part of the name Dublin and modern Welsh llyn) and refers to the Brayford Pool.

In the late 19th century, the surnames Lindsay and Lindsey began to be used as given names, at first only as masculine names. They remained typically masculine until the 1960s in Britain and the 1970s in the United States. They are both now feminine names in the United States. In Australia, New Zealand, and Scotland, Lindsay remains popular for masculine use and Lindsey has mainly become feminine. As a first name, Lindsey was the 570th most popular name for girls born in the United States in 2014, while Lindsay ranked 653rd. Both spellings ranked among the top 100 names for girls from 1980 through 1993, with Lindsey peaking at #35 in 1983 and 1984 and Lindsay peaking at #36 in the same years.

Common alternative spellings of this name include but are not limited to: Lindie, Lindy, Linni, Linnie, Linny, Linds, Linza, Elle, Ell, Ellie, Ella.