The AEG G.III was a biplane bomber built by the (AEG) during the First World War for the Imperial German Army's () Imperial German Air Service (). It was an enlarged version of the G.II fitted with more powerful engines for the same battleplane () or aerial cruiser role escorting bombers or reconnaissance aircraft and engaging enemy aircraft. The prototype was completed in December 1915, but deliveries did not begin until May 1916.
The Inspectorate of Flying Troops ( () ordered the prototype of the G.III (factory designation GZ3) on 1 April 1915 with the intention of using it as a battleplane like its predecessor. The G.III was to be equipped with a pair of the most powerful engines available and AEG selected the water-cooled Mercedes D.IV straight-eight piston engine. Other requirements included a crew of three, of armor and a bomb load of . Its defensive armament was to consist of a pair of 7.92 mm (.312 in) machine guns or a cannon in the nose and a dorsal machine gun. The aircraft had to use four-bladed propellers to absorb the power of the engines. These tended to break their crankshafts in service as they were not well supported by bearings.
ordered a batch of five G.IIIs on 7 September 1915 before the first prototype was completed in December; one of these was fitted with a triple rudder like the modified G.IIs used for comparison with the single rudder used by the prototype. The single rudder proved to be superior and it was used by all the G.IIIs. Forty more aircraft were ordered in two batches in December 1915 and March 1916. The first three production aircraft were delivered in May and G.IIs were on the front line strength reports the following month. The aircraft equipped Bomber Wing 1 () that operated on the Macedonian Front. The last time that any G.IIIs show up on the bimonthly strength reports is on 30 April 1917.