A method for sound radiation analysis of laminated composite plates partially supported by flexible supports is presented. In the vibration formulation of the plate, each of the flexible edge supports of the plate is modeled as a continuously distributed spring system. The Ritz method is used to approximate the vibration shapes of the flexibly supported laminated composite plates. The equations of motion of the plate are formulated via an energy approach. The sound pressure level (SPL) curve of the plate subjected to different excitation frequencies is constructed using the first Rayleigh integral. The capability of the proposed method in predicting acceptable SPL curves for flexibly supported laminated composite plates is validated by experimental data. A number of numerical examples are given to study the effects of vibration mode shapes and supporting conditions on the SPL curves of laminated composite plates. It has been shown that for the plates under consideration, the supporting conditions can have some effects on the sound radiation of the plates and the first bending mode shapes of the plates can cause significant drops on the SPL curves of the plates.