Brunei Bay (Malay: Teluk Brunei) is on the northwestern coast of Borneo island, in Brunei and Malaysia.

Brunei Bay is located 500'43.44", 11517'26.66"; east of Bandar Seri Begawan, Brunei.

It is the ocean gateway to the isolated Temburong District of Brunei, separated from the rest of Brunei by the Malaysian Sarawak State surrounding it to the bay.

A 30-kilometre (19 mi) roadway connecting the Muara and Temburong districts of Brunei, completed in 2018, crosses over the Brunei bay. The section going across the Brunei bay measures in at 14-kilometre (8.7 mi).

The Second Australian Imperial Force (Second, or 2nd, AIF) was the name given to the volunteer personnel of the Australian Army in World War II. Under the Defence Act (1903), neither the part-time Militia nor the full-time Permanent Military Force (PMF) could serve outside Australia or its territories unless they volunteered to do so. The Second AIF fought against Nazi Germany, Italy, Vichy France and Japan. After the war, Australia's wartime military structures were demobilised and the 2nd AIF was disbanded, although a small cadre of its personnel became part of the Interim Army that was established in 1947, and from which the Australian Regular Army was formed in 1948.