The geodynamic evolution of rifted continental margins is discussed, based on preliminary results from a thermo-mechanical model. This model uses the temperature distribution predicted by extension of the lithosphere during rifting to derive the mechanical properties of the lithosphere which in turn determine its response to loading by sediments and water. The model predicts the evolution of the marginal sedimentary basin, the configuration of the crust-mantle boundary, and the gravity anomalies, all of which result from extension during rifting and from the isostatic response to loading. The properties are described in general terms and are also shown to compare favourably with observational data on the Nova Scotian continental margin.