This paper investigates the importance of accounting for the dynamic behavior of the rigid pavement system during falling weight deflectometer (FWD) testing. An analytical closed-form solution for dynamic loading of a plate on the Winkler foundation is derived and, using this solution, FWD sensor deflections are simulated and compared with the measured deflections. The lag between the peak of the applied FWD load and sensor deflections can be explained by the effects of pavement inertia and subgrade dumping. Nondimensional parameters that govern the dynamic behavior of a rigid pavement system are also identified.