A microstructure model of polymer rheology is applied to study the behavior of the dynamic viscosities under superposed in‐line and transverse oscillations. A general solution valid to first order in oscillatory shear rate is obtained, and the limiting cases of small and large values of the frequency of oscillation are examined. The results for these limiting cases are found to be in agreement with results based on the incompressible BKZ and simple fluid models. A solution valid to third order in oscillatory shear rate is obtained, and for this case the shear stress response is found to contain harmonics of the driving frequency.