This invention relates to a mounting structure (1) for mounting an engine (2) under an aircraft wing (4), the structure comprising a rigid structure (8) and means (10) of fastening this rigid structure under the wing, the mounting means comprising a forward fastener (14), an intermediate fastener (15) and an aft fastener (16). According to the invention, the forward fastener has at least one triangular shackle on each side of a vertical plane passing through a longitudinal axis (5) of the engine (2), placed in a vertical plane oriented along a longitudinal direction (X) of the aircraft. Furthermore, the intermediate fastener comprises a connecting rod capable of transferring forces applied in a direction (Y) transverse to the aircraft, and the aft fastener comprises at least one shackle oriented along a vertical direction (Z) of the aircraft.