Misfit dislocation glide velocities have been measured in Si/Si1−xGex/Si heterostructures. Si capped single Si1−xGexalloy layers and multiple quantum well geometries were investigated and no difference was found between dislocation kinetics in these structures and the equivalent alloy layer of the same average composition. Velocities in the range 25 nm s−1to 2 nm s−1were determined from the length ofa/2⟨110⟩ 60° type misfit dislocation segments after annealing in the temperature range 450–950 °C, for times between 5 and 2000 s. Two dislocation mechanisms were observed; a single misfit array at the first Si1−xGex/Si interface was found in multiple quantum wells and alloy layers while paired misfit segments were observed at both strained interfaces in Si capped Si1−xGexalloy layers. An expression for the effective stress, &tgr;eff, for single and paired misfit dislocation propagation is presented which accommodates variation in the unstrained Si cap thickness. The mean activation energy for misfit disclocation glideQvfor Si1−xGex/Si heterostructures with 0.035<x<0.25 was found to be 2.25±0.05 eV andQvwas independent of &tgr;eff. For all geometries and for &tgr;effin the range 100–750 MPa the misfit dislocation glide velocity can be defined byV(mm s−1)= (4±2)×1014(&tgr;eff/&mgr;)2 exp−(2.25/kT).