Large lateral variations in the thickness of the lithosphere and viscosity of the mantle may be associated with continental roots. The effects of continental roots, or the tectosphere, on postglacial rebound are calculated using an axisymmetric flow model in which both the mantle and lithosphere are described as Newtonian fluids. Continental roots are shown to have a measurable effect on postglacial rebound, in particular, on the evolution of the peripheral bulge. Effects of continental roots are concentrated near the edge of the tectosphere, and thus often near ocean-continent boundaries where many relative sea-level histories are measured. The pattern and distribution of tectonic and seismic activity associated with deglaciation are affected by a tectosphere. ¿ American Geophysical Union 1995