The effects of Nb2O5 addition and MnO2‐Nb2O5 co-addition on the piezoelectric properties of Pb(Zr0.53Ti0.47)O3 (PZT) ceramics are investigated. When Nb2O5 is added to PZT, the planar coupling factor (Kp) significantly increases but the mechanical quality factor (QM) as well as the electrical quality factor (QE) decreases. When MnO2 and Nb2O5 are co-doped, QM increases remarkably while Kp rarely changes. This increase in QM is ascribed to the domain pinning by Mn as is the case of previously reported MnO2-doped PZT, and the negligible change in Kp is ascribed to the barely changed tetragonality. Even though MnO2-Nb2O5 co-doped PZT shows a smaller induced strain than that of Nb2O5- doped PZT, excellent temperature stability is obtained. It is shown that MnO2‐Nb2O5 co-doped PZT may be a very suitable material for high-power piezoelectric actuators because of its high Kp, QM and QE, its low dielectric constant and its excellent temperature stability.