Abstract: The present invention relates to a turbofan jet engine nacelle intended to be attached to a structure of an aircraft by an engine strut and comprising a forward air inlet section, a mid-section intended to surround a jet engine fan, and an aft section having an internal structure intended to serve as a casing for an aft portion of the jet engine and, together with an external structure (5), defining a flow duct (7) for a secondary stream, the internal structure having substantially radial extensions (61) passing through the duct and via which it is connected to an inner panel (51) of the external structure by means of at least one corresponding stiffener (110) having a right-angled general shape, characterized in that the stiffener is also fastened in an external panel (52) of the external structure.