In Part I of this article, the authors have reviewed several methods of interphase characterization; the review consisted of principal interphasial characterization methods and several recent techniques for the physical characterization (evaluation of thickness, volume fraction, Young's modulus, shear modulus, and coefficient of thermal expansion) of the interphase. Models of physical properties (thickness, Young's modulus, Poisson's ratio, and coefficient of thermal expansion) of the interphase have been considered by several researchers in an effort to study the influence of the interphase on overall composite properties and behavior. Hypotheses on interphase formation and properties have been proposed and tested by some researchers. This article presents a review of these interphase models and discusses their salient features. Both experimental characterization as well as modeling studies are necessary to achieve a more profound understanding of the interphase and its behavior.