In this work, a silica-based glass-ceramic coating has been deposited on higher manganese silicide (HMS) thermoelectrics in order to provide oxidation protection at high temperature (up to 600 degrees C). The coating showed good densification behaviour and an excellent thermomechanical and chemical compatibility with the HMS substrate, suppressing the silica scale formation on the HMS at high temperatures. The thermoelectric properties of the glass-ceramic-coated HMS showed excellent stability after oxidation at 600 degrees C in air for 500 h.