A cohesive zone type model, taking full account of finite geometry changes, is used to provide a unified framework for describing the process of interfacial decohesion from initial debonding through complete separation. Constitutive relations are specified independently for material phases and for the interface. This model permits the prediction of interfacial decohesion without the necessity of introducing some additional failure criterion. Also, since the mechanical response of the interface is specified in terms of both a critical interfacial strength and the work of separation per unit area, dimensional considerations introduce a characteristic length. Various issues associated with the analysis of interfacial failure phenomena within this framework will be discussed.