No. 1 Operational Training Unit (No. 1 OTU) was an operational conversion unit of the Royal Australian Air Force (RAAF) during World War II. Formed in December 1941 at RAAF Station Nhill, Victoria, it relocated to RAAF Station Bairnsdale in mid-1942, and then to RAAF Station East Sale the following year. No. 1 OTU's primary role was to train aircrew for multi-engined aircraft operations. At its peak of activity in August 1944, it was operating over 130 aircraft, the most numerous being Bristol Beauforts. Its aircraft and personnel also conducted transport missions in New Guinea and maritime patrols in southern Australian waters. Following the end of hostilities, the unit was disbanded in December 1945.