The effect of hollow ceramic spheres embedded in the epoxy matrix on the dielectric behavior of composite was investigated in the 100 Hz to 100 kHz range. It was found that the dielectric constant of epoxy matrix can be reduced by mixing the matrix with hollow ceramic spherical inclusions. To predict the effective dielectric constant of the composite, effective medium theory based on Clausius-Mossoti equation was used. It was found that predictions for effective permittivity, based on this relation, correlate well with experimentally obtained results in the entire frequency range of investigation.  To compensate for the degradation of the mechanical properties of the epoxy matrix, which resulted from the incorporation of the spheres into the structure, E-glass fibers, at low fiber volume fraction, were added. The dielectric response of the epoxy-ceramic spheres-glass fibers system was studied, and it was found that this type of composite structure can be used to produce materials with tailored dielectric properties