A modular elevator system has a pit module, one or more shaft modules that are attachable to the pit module and/or to an adjacent shaft module, and a cap module that is attachable to an uppermost shaft module. The pit module, the shaft modules, and the cap module are each pre-fabricated and transported to a site at which a building is under construction for assembly top of the pit module, the remaining shaft modules are secured sequentially on top of each other, and the cap module is secured on top of the uppermost shaft module.