Abstract: A mute holder for a musical instrument such as a trumpet, cornet, or trombone, as a clamp portion for attaching to a music stand, and a ring portion for holding the mute. The ring portion has a C-shaped fixed arcuate member and a pivoting sector that allows the mute to be taken out or replaced from the side. A spline-type joint between the clamp and the ring portion locks the angle of the mute holder at a selected one of a number of possible angles. A cam and lever clamp arrangement has several flat surfaces and adapts to fit music stands of any of a number of thicknesses.