Slab detachment (or break-off ) is the process during which subducting lithosphere becomes detached from the surface plate. Knowledge of the dynamics of slab break-off and its signature in the overlying surface contributes to a more complete understanding of the deformation and fate of subducted slabs and may provide constraints on the rheology of subducting lithosphere and the upper mantle. Evidence of the process includes gaps in hypocentral distributions and within tomographic images of subducted slabs. An increasing number of recent studies acknowledge slab detachment as a real process with observable surface effects such as uplift, magmatism, and cessation of subduction in regions including the Alps, Mediterranean-Carpathian Region, New Hebrides Islands, Aleutian-Kamchatka junction, and Ba ja California. In particular beneath the Trans-Mexican Volcanic Belt, propagation of a volcanic pulse may correspond to a propagating tear in the subducted Farallon plate, and an understanding of the dynamics of break-off is needed to determine the sequence and cause-and-effect relationships between cessation of subduction, detachment of the subducted Farallon plate, and volcanism. Previous investigations have focused on 2D static models and force balance calculations to determine the feasibility of slab break-off, and a few have assessed the maximum surface uplift and thermal effects of shallow detachment to explore the ranges of possible effects. More recent 2D numerical models have indicated that following the cessation of subduction, necking of the slab and rapid detachment occur over a few million years. We present fully dynamic numerical flow models exploring the process of slab detachment. The models employ a rheology in which the total strain rate is accommodated by diffusion and dislocation creep, and a yield stress criteria is used for the cold slab interior. Our study investigates the effect of a slab’s thermal structure, which depends on plate age and subduction velocity and affects buoyancy and strength, on the timing of detachment and resulting deformation of the overriding plate. In addition to thermal structure effects, we demonstrate the influences of slab length and maximum yield strength of subducting lithosphere on the timing and morphology of detachment, resulting surface deformation, and the dynamics of the detached slab within the mantle.