During World War II, Imperial Japan invaded most of the former western colonies. The Shōwa occupation regime committed violent actions against civilians such as the Manila massacre and the implementation of a system of forced labour, such as the one involving 4 to 10 million romusha in Indonesia. A later UN report stated that four million people died in Indonesia as a result of famine and forced labour during the Japanese occupation. The Allied powers who defeated Japan in the South-East Asian theatre of World War II then contended with nationalists to whom the occupation authorities had granted independence.

The western colonies were invaded by whom during World War II?