A recently formulated porous interface layer model is employed to study the influence of bond defects particularly due to the presence of voids in interface zones on Lamb wave propagation in a laminate made of two identical fiber‐reinforced laminas. The model is developed making use of the mathematical theory of linear elastic materials with voids to describe the interface zone−the adhesive with its minute separation from the adherent laminas. Theoretical Lamb‐mode dispersion spectra in a symmetric bilaminate made of boron fiber‐reinforced aluminum sheets are obtained and compared with those obtained assuming perfect bond condition. It is hoped that the model will facilitate ultrasonic nondestructive evaluation of bond strengths in composite laminates.