Rainbow ceramics of selected compositions near the morphotropic phase boundary of the PLZT system were characterized with respect to their piezoelectric properties for potential applications in stress sensing and measurement. Electrical signals induced under a steady-state point load and pressure were determined for samples having various dimensions, thickness ratios, and sizes of electroded area. It was found that the Rainbow samples exhibited a strong piezoelectric effect when they were operated in the dome mode. The corresponding effective piezoelectric coefficient could be over two orders of magnitude greater than that of the original unreduced ceramics, depending on the geometry and composition of the samples. Using a comparison method, the voltage sensitivity of the Rainbow samples was evaluated as a function of the frequency of applied pressures. The sensitivity showed a progressive decrease with increasing frequency at frequencies below approximately 5 Hz, followed by a relatively flat response zone with corresponding values around -190 dB before occurrence of the mechanical resonances. The stress distribution and induced voltage signal in a Rainbow under external loading were analysed using a finite element model. Results of this investigation indicate that Rainbow ceramics offer significant advantages over unreduced samples for stress-sensing applications involving low stress levels and frequencies.