The Bankstown Bunker, formerly known as Air Defence Headquarters Sydney (ADHQ Sydney), is a heritage-listed defunct Royal Australian Air Force (RAAF) operations facility, located on the corner of Marion and Edgar Street, in Condell Park, New South Wales, Australia. It was designed by the Allied Works Council and built from 1943 to 1944 by Stuart Bros Pty Ltd of Sydney. It is also known as Air Defence Headquarters Ruin Sydney (former), No. 1 Fighter Section Headquarters, 1FSHQ, Bankstown Bunker and RAAF No. 1 Installation Bankstown; No. 101 Fighter Sector. It was added to the New South Wales State Heritage Register on 18 November 2011.
After the arrival of General Douglas MacArthur in Australia during World War II, Bankstown Airport was established as a key strategic air force base to support the war effort. During this period the specially constructed bunker became an important RAAF headquarters from 1945 until its closure in 1947. The Bankstown bunker is currently buried under a public park which lies at the end of Taylor Street, and is not accessible by the general public.