Johann Nikolaus Hanff (25 September 1663 – 25 December 1711) was a North German organist and composer. Hanff was born in Wechmar in Thuringia and worked in Eutin, Hamburg and Schleswig. While in Hamburg, Hanff taught harpsichord and composition to the young Johann Mattheson for four years. Mattheson was to become a composer, music theorist and close friend of George Frideric Handel (who almost killed Handel in a duel).