The Second Battle of the Java Sea was the last naval action of the Netherlands East Indies campaign, of 1941–42. It occurred on 1 March 1942, two days after the first Battle of the Java Sea. It saw the end of the last Allied warships operating in the waters around Java, allowing Japanese forces to complete their conquest of the Dutch East Indies unhindered.

The Dutch East Indies campaign of 1941–1942 was the conquest of the Dutch East Indies by forces of the Empire of Japan in the early days of the Pacific campaign of World War II. Allied forces attempted unsuccessfully to defend the islands. The East Indies were targeted by the Japanese for their rich oil resources which would become a vital asset during the war. The campaign and subsequent three-and-a-half-year Japanese occupation was also a major factor in the end of Dutch colonial rule in the region.