As adoption of offsite methods of production continues to grow within the construction industry, optimization techniques from manufacturing are increasingly being utilized analogously for increasing productivity, reducing rework, and improving assembly processes. This paper demonstrates how the concept of selective assembly can be applied in modular construction as a potential assembly optimization technique. Rather than specifying and controlling tight fabrication tolerances, the selective assembly process groups components into bins or categories of compatible dimensional and geometric properties in order to find an optimal arrangement of interchangeable components in an assembly. This concept has traditionally proven to be more cost effective in certain manufacturing applications than using rigorous specification and control of tight fabrication tolerances. Using a laser scanner for as-built data acquisition, a modular steel bridge is analyzed as a case study to demonstrate how the concept of selective assembly can be applied in modular construction. The results of this case study show that selective assembly has potential to reduce rework in certain modular construction applications.