We derive an analytical expression to predict the effective properties of a particulate-reinforced piezoelectric composite with interfacial imperfections using a micromechanics-based mean-field approach. We correctly derive the analytical formula of the modified Eshelby tensor, the modified concentration tensor, and the effective property equations based on the modified Mori-Tanaka method in the presence of interfacial imperfections. Our results are validated against finite element analyses (FEA) for the entire range of interfacial damage levels, from a perfect to a completely disconnected and insulated interface. For the facile evaluation of the nontrivial tensorial equations, we adopt the Mandel notation to perform tensor operations with 9 x 9 symmetric matrix operations. We apply the method to predict the effective properties of a representative piezoelectric composite consisting of polyvinylidene fluoride (PVDF) and SiC reinforcements.