Kastrup is a suburb of Copenhagen, Denmark, situated on the east coast of Amager in Tårnby Municipality. It is best known as the site of Copenhagen Airport. In Danish, the airport is often called Kastrup Lufthavn (Kastrup Airport) or Københavns Lufthavn, Kastrup (Copenhagen Airport, Kastrup). The population of Kastrup is approximately 43,000.

In 1749 Jacob Fortling obtained a royal license to establish a lime plant in Kastrup. It harbor in Kastrup for the landing of chalk from Saltholm. He soon diversified with a brickyard (1752) and a pottery specializing in faience (1755) at the same site. This marked the beginning of an industrial development that accelerated after the opening of Kastrup Glassworks in 1847. Copenhagen Airport opened in 1925.

Local landmarks include the National Aquarium Denmark, Kastrup Værk, Kastrupgaard and Kastrup Church.