Gustav Adolf Merkel was a German organist and composer.
His compositions include nine organ sonatas (which have been recorded several times, as well as occurring quite often in organ recitals), plus a separate sonata for two organists (his Opus 30), and several dozen miniatures (some of them based on Protestant chorale melodies). In these works his style is broadly conservative, very much influenced by Mendelssohn, and with similarities to the output of his younger contemporary Josef Rheinberger. He also produced choral and piano pieces; his salon piece "Schmetterling" ("Butterfly"), Op. 81, No. 4 is particularly well-known.
