We investigate the effect of strain on the etching rate of two SiGe selective wet etchants, namely NH4OH:H2O2 and H2O2, which are currently used to investigate the composition of strained SiGe layers. We measured the etching rates for relaxed Si1−xGex layers and for layers under a ±0.84% biaxial strain with different nominal Ge fraction x. For both etchants, we found that there is no appreciable strain sensitivity, i.e. the etching rates do not depend on the actual strain state in the SiGe films. Instead, for the NH4OH:H2O2 solution, the rates are primarily determined by the Ge content. Finally, we show that both etchants are isotropic with no preferential etching of particular facets.