In this paper an analytical model based on finite element energy formulation that calculates free vibration frequencies of cantilevered-free laminated double lap bonded joints is established. 8-noded serendipity element with quadrature Gaussian formula was adopted. This model was validated using 3D finite element model through ANSYS Workbench. The results have shown good agreement for steel and composite while it was not the case for polymeric substrates. Moreover, an experimental procedure for analysing the vibrational response of adhesively composite double lap joints is presented in this paper. The Impulse Excitation Technique (IET) has been adopted in order to measure the resonant frequencies. Two types of substrates were examined: steel and orthotropic glass-polypropylene composite and the adhesive used is a resin/epoxy constituent. Three different substrates thicknesses and three different overlap lengths were examined. Then, the experimental results were compared with numerical simulations using 3D finite element model through ANSYS Workbench. The results have shown good agreement between both models. Finally, the analytical model was applied to compare the experimental results in the scope of a parametric study towards the influence that some geometrical and mechanical properties of the adherents have on the vibrational response of the structure.