Air Vice Marshal Julie Hammer, AM, CSC, FTSE, FRAeS (born 17 February 1955) is an Australian engineer and a retired senior officer in the Royal Australian Air Force (RAAF). She was the first woman to be promoted to one-star rank, and also the first woman to be promoted to two-star rank, in the Australian Defence Force. She was also the first woman to command an operational unit in the RAAF.