Arnold Matthias Brunckhorst (1670–1725) was a German organist and composer.
He was born in Celle or Wietzendorf. Beginning in 1693, he served as an organist at St. Andreas in Hildesheim. In 1697, he assumed the organist's post at the Stadtkirche in Celle. In 1720, he was appointed court organist at Hanover.
Only a few works by him have survived: two small oratorios - for Christmas and Easter, one single-movement keyboard sonata in A major (regarded as the earliest German documentation of the form of the two-part sonata structure, comparable to the formal type encountered in Domenico Scarlatti), and a praeludium in E minor for organ.
Brunckhorst Opera omnia complete works: Weihnachts-Historie, Prelude for Organ in E minor.
Oster-Historie, Harpsichord Sonata in A major. Musica Poetica Freiburg, dir. Hans Bergmann