Amager ([ˈɑmɑːˀ] or, especially among older speakers, [ˈɑmæːɪ̯ˀɐ]) is a Danish island in the Øresund. The Danish capital, Copenhagen, is partly situated on Amager, which is connected to the much larger island of Zealand by five bridges.

Amager has long been populated, and well used, thanks to its rich soil and proximity to Copenhagen. In 1521, Christian II invited some Dutch farmers to move to Amager and grow vegetables to supply the Danish Court and Copenhagen. It was only in the late 19th century that Copenhagen began to expand onto the island (Sundbyerne), and in 1902 these built-up areas were incorporated into Copenhagen.

During the Second World War, high unemployment in Copenhagen led authorities to drain a large part of the sea, west of the island, and build a dam to hold out the water, effectively adding one half of Amager's previous area to the island.

The reclaimed area is currently known as Kalvebod Fælled, and was originally a military area, but today it is part of a major construction area called the Ørestad, being thought of as an extension to central Copenhagen. The area houses such major facilities as the Bella Center, a convention and exposition center, and Field's, the second-largest shopping center in Scandinavia. This project was initiated by the Danish government.

Amager Vest is one of the ten administrative district of Copenhagen, Denmark, located on in the north-western part of the island of Amager. It includes areas such as Islands Brygge, Ørestad and Eberts Villaby as well as the extensive meadowland of Kalvebod Fælled. Western part of Amager island is mainly an enlargement from shallow parts of the Øresund sea. The extension of western Amager began around 1930 and was finished around 1955. The main purpose was to give shelter to the southern parts of Copenhagen harbour. The enlargement is filled with rocks, sand from the sea, plaster, waste and today unknown items making it very expensive to set up buildings here. The exhibition centre Bella Center (which hosted the environment meeting COP15 in December 2009) is one of very few exception from this. Even the soil is to bad for agricultural matters. Western Amager is the largest of the ten new official boroughs of Copenhagen, but has at the same time the smallest population. Only the most northern part can be considered as "urban area"