Example folding door thrust reversers for aircraft engines are disclosed herein. An example apparatus includes a nacelle of a turbofan engine, where a fan duct is defined between the nacelle and a core of the turbofan engine. The example apparatus includes an opening in the nacelle between an outside of the nacelle and the fan duct and an inner door and an outer door disposed within the opening and pivotably coupled to the nacelle along aft edges thereof. The example inner and outer doors are pivotable between a first position in which the inner door and the outer door are disposed within the opening and oriented substantially parallel to each other, and a second position in which the inner door is disposed in the fan duct and oriented substantially perpendicular to an outer surface of the core and the outer door extends outward from the nacelle.