Stacked semiconductor assemblies, and related systems and methods, are disclosed herein. A representative stacked semiconductor assembly can include a lowermost die and two or more modules carried by an upper surface of the lowermost die. Each of the module(s) can include a base die and one or more upper dies and/or an uppermost die carried by the base die. Each of the dies in the module is coupled via hybrid bonds between adjacent dies. Further, the base die in a lowermost module is coupled to the lowermost die by hybrid bonds. As a result of the modular construction, the lowermost die can have a first longitudinal footprint, the base die in each of the module(s) can have a second longitudinal footprint smaller than the first longitudinal footprint, and each of the upper die(s) and/or the uppermost die can have a third longitudinal footprint smaller than the second longitudinal footprint.