The theological behavior of multilayer polymeric structures has been investigated. Measurements of the bulk viscoelastic properties via small-amplitude oscillatory rheometry indicated that the shear viscosity is independent of both the number of layers (83 vs. 165) and the composition (30/70, 50/50, and 70/30 PC/PMMA by weight) within the limits of the data obtained. It is also apparent that the shear viscosity is influenced strongly by the skin layer material. In addition, a model has been developed that can be used to predict the shear viscosity and sheat stress of a multilayer structure experiencing shear now. The model predicts that the sheat viscosity of a multilayer structure should be independent of the number of layers and strongly dependent on the material in the skin layer. These predictions are in agreement with experimental data.