The focus of this paper is to investigate numerically the vibro-acoustic responses of functionally graded lightweight square panel (FGLSP) made from Al/Al2O3 with various boundary conditions (BCs). The approach of analysis is restricted to low and mid-frequency regions. First-order shear deformation theory and finite element method are employed to model the vibro-acoustic response of the FGLSP. Its properties vary along its thickness and are obtained by the Voigt’s rule of mixture as well as a simple power law distribution. Modal responses of pristine aluminium material (PAM) obtained analytically and experimentally are used to validate the numerical approximation of modal responses of PAM. These results are used to compare the numerical results of FGLSP and the first twelve mode shapes are obtained for all BCs. A comparison of the result shows that at low and mid-frequency regions, the sound transmission loss of FGLSP is higher than the conventional PAM. The study reveals that FGLSP can compete favourably with their pristine material counterparts. This material are particularly useful for noise reducing casings which surround noisy devices, household appliances or industrial machines, and limit noise transmission to the environment.