||This study uses model pile load testing combined with numerical analysis to investigate the pile response as well as soil reaction, and p-y curve analysis due to the flexural yielding of a pile, and to examine the applicability of the distributed plastic hinge model to simulate the inelastic pile response. Two successive lateral load tests on an aluminum model pile in sand were conducted for this study. In the first test, the pile was subjected to a small lateral pile-head displacement, a displacement under which the pile remained elastic. In the second test, the pile was loaded to a much larger lateral pile-head displacement, a displacement under which some of the pile sections yielded and thus the pile had inelastic flexural deformation. Comparison of the results of both tests shows that before the pile yielded, the depth of maximum moment increased with increasing load due to soil nonlinearity; after the pile yielded, the depth of maximum moment varied less and the plastic region expanded upward and downward around this depth with increasing pile displacement. In developing the p-y responses for the pile-soil system, a correct nonlinear flexural rigidity of the pile section is essential to retrieve rational ones. In addition, the distributed plastic hinge model is shown to be effective to model the inelastic pile response and capture the development of plastic zones in the pile.