Abstract: A harmonica support clamp which attaches any standard harmonica to any standard vocalist-type stand-held microphone. Which harmonica support clamp comprising a hollow, one-piece extruded plastic body open at both ends and with two juxtaposed harmonica-clamping edges; each of which harmonica-clamping edges extends the length of an attached clamping side wall and is formed simultaneously with and as a part of the associated clamping side wall; and between which harmonica-clamping edges a harmonica is receivable. Each clamping side wall is a continuation of a common central base wall.