A simple mathematical model using polynomial functions is presented for uniaxial cyclic behavior of clay brick masonry under compressive loading. The proposed model predicts the reloading and unloading stress-strain curves at different values of plastic (residual) strains, for both cases of loading, i.e., loading perpendicular to the bed joint and loading parallel to the bed joint. The model transfers the reloading and unloading curves to a normalized stress-strain coordinate system on which the reloading and unloading curves plot within a narrow range. A parent polynomial is then developed to fit the curves on this coordinate system. The individual reloading and unloading curves can then be produced by transferring the parent equation to the stress-strain coordinate system. Comparison between the experimental and computed stress-strain curves shows good correspondence.