Electron cyclotron resonance etch rates for GaN, InN, and AlN are reported as a function of temperature for Cl2/H2/CH4/Ar and Cl2/H2/Ar plasmas. Using Cl2/H2/CH4/Ar plasma chemistry, GaN etch rates remain relatively constant from 30 to 125 °C and then increase to a maximum of 2340 Å/min at 170 °C. The InN etch rate decreases monotonically from 30 to 150 °C and then rapidly increases to a maximum of 2300 Å/min at 170 °C. This is the highest etch rate reported for this material. The AlN etch rate decreases throughout the temperature range studied with a maximum of 960 Å/min at 30 °C. When CH4 is removed from the plasma chemistry, the GaN and InN etch rates are slightly lower, with less dramatic changes with temperature. The surface composition of the III–V nitrides remains unchanged after exposure to the Cl2/H2/CH4/Ar plasma over the temperatures studied.