For the purpose of converting the mechanical energy of surface waves on bodies of water, a power generating piezoelectric structure (10) is provided comprising piezoelectric material members, preferably in the form of one or a laminate of sheets (14) of such material, each sheet having an electrode (24) on opposite surfaces thereof. Each pair of electrodes and the piezoelectric material therebetween define a power generating element, each of which is preferably dimensioned, relative to the wave lengths of selected waves on the body of water in which the generator is to be used, for increasing the efficiency of power conversion. A support (12) is provided for maintaining the structure in a preselected position within and below the surface of the water. Preferably, the pizoelectric generating elements are flexible and are supported in such manner to allow flexure thereof in response to movement of the surrounding water. In certain embodiments the elements are designed to enter into mechanical resonance in response to the passage of waves thereover, such flexure and/or resonance increasing the mechanical coupling efficiency between the waves and the elements.