This review article summarizes applications of the interferometric strain/displacement gage (ISDG). The laser-based ISDG measures in-plane surface deformation between two small reflecting surfaces by monitoring the interference fringe pattern motion. The short gage length (100 micrometers) and noncontacting nature are especially attractive in certain laboratory situations. Following a discussion of the measurement procedures, applications in dynamic loading, fatigue and fracture, and high temperature environments are reviewed.