Using the mixed experimental/numerical method, the frequency-dependent transverse shear moduli (TSM) and damping values of the commercially available Nomex honeycomb cores were investigated. Four kinds of honeycomb cores with different phenolic resin thicknesses were used to explore the effect of the phenolic resin thickness on these dynamic mechanical properties. Results reveal that both the TSM and damping values have positive logarithmic relationships with the frequency, and the sensitivity of these dynamic mechanical properties to frequency is higher for the honeycomb core with thicker phenolic resin. Among all the transverse shear directions, TSM and damping values in the LT direction are the highest at medium and high frequencies. Compared with the damping values, the effect of phenolic resin thickness on TSM is more obvious. Therefore, it is a more efficient way to enhance the TSM than to improve the damping values by controlling the thickness of phenolic resin.