Bigej or Begej /ˈbiːdʒiː/ (Marshallese: Pikeej, [pʲiɡɛːtʲ]) Island is part of Kwajalein Atoll in the Ralik Chain in the Republic of the Marshall Islands (RMI), 2,100 nautical miles (3900 km) southwest of Honolulu, Hawaii.

The remains of a fuel tank farm built by the US Navy in 1944 are still present on the island. Bigej is not part of the Reagan Test Site.

Bigej is inhabited by a small Marshallese population and has several buildings on it. Many people from Kwajalein island in the south of the atoll come up to visit it for water sports such as snorkeling and floating. Out of respect for the landowners anyone who wishes to go onto the island is asked to gain permission before doing so.

It is covered with lush tropical palm trees and jungle. It is a site of cultural significance to the indigenous people of Kwajalein, as are most of the small islands throughout the atoll.

8°53′39″N 167°46′21″E / 8.89417°N 167.77250°E / 8.89417; 167.77250