Plasma etching characteristics of common wide bandgap compound semiconductors including III-nitrides (gallium nitride, aluminum nitride, and indium nitride) and their alloys and silicon carbide (SiC) are discussed in this entry. Sophisticated electronic and photonic devices are mainly based on these wide bandgap materials, which are required to be etched by dry plasma etching systems due to the inadequacy of wet etching techniques. Major dry etch techniques including reactive ion etching (RIE), inductively coupled plasma (ICP) etching, electron cyclotron resonance (ECR) etching, and inductively coupled plasma reactive ion etching (ICP-RIE) are briefly mentioned to study etch characteristics. Most commonly used plasma chemistries, particularly fluorine-based and chlorine-based, which have been used for these materials are reviewed. Critical points regarding device fabrication such as anisotropy and selectivity are discussed. The effect of system parameters, particularly plasma composition on the etched surface morphology, is analyzed in detail for etching n-type SiC epitaxial layers.