A window well assembly for buildings and the like include at least a first well unit and a second well unit each having opposite first and second flanges at opposite ends of a retaining wall of each unit for securing the well units to a sub-grade foundation of the building. Preferably, the assembly has a plurality of releasable spacer couplings that are mated and carried between well units when the assembly is in a stored state, and has indexing features that are mated and carried between well units when the assembly is in an assembled state.