A musical instrument mute retention assembly with perpendicular mounting flange mount to a music stand at a parallel disposition with the ground surface, while also retaining multiple instrument mutes of various sizes and musical-related items in a level, upright disposition. The assembly provides a mute panel defined by mute apertures disposed in a linear, spaced-apart relationship. The mute panel also provides music item apertures disposed in a linear, spaced-apart relationship, and further being parallel to the mute apertures. A mounting flange fixedly attaches to the mute panel in a perpendicular disposition. The mounting flange interfaces with a gapped flange that extends from a sloped support panel of a music stand in slidable or fastenable engagement. Because the mounting flange is perpendicular to the mute panel, the retained mutes and music-related items are maintained parallel with the ground surface, facilitating access to the apertures and retained mutes.