Reactive ion etching is important for III‐V device fabrication. Commonly encountered applications include the need to remove an epitaxial layer selectively from underlying layers and the need for definition of mesas and other structures with carefully controlled dimensions. We present results showing the use of very thin Al0.9Ga0.1As and In0.2Ga0.8As stop‐etch layers, which when used in conjunction with a particular etch chemistry can provide highly selective removal of epitaxial layers in GaAs‐based III‐V compound semiconductors. In addition, we report the selective removal of an Al0.3Ga0.7As layer from underlying GaAs by the use of a thin In0.2Ga0.8As interlayer.