We investigate the size-dependent behavior of Miura-ori-based origami tessellations by changing the number of origami unit cells. While large Miura-ori tessellations generally exhibit a negative in-plane infinitesimal Poisson’s ratio, small tessellations can reach a zero-Poisson’s-ratio state during deployment. At this state, the structure becomes kinematically locked, as pure origami folding no longer permits deformation along one direction of cell repetition. We derive the condition for this zero-Poisson’s-ratio state to occur during deployment and show that it is governed by the tessellation size. This size-dependent locking is validated through compression experiments. Extending the analysis to three-dimensional Miura-ori tube structures, we find that the direction of kinematic locking also changes depending on the tessellation size. These results establish the tessellation size as an important geometric control parameter for both the onset and direction of locking in origami metamaterials.