Kaspar Fürstenau (26 February 1772, Münster – 11 May 1819, Oldenburg) was a German flautist and composer. He wrote about sixty compositions for his instrument among rondos, fantasias, suites and concertos. Together with his son Anton Bernhard Fürstenau he traveled extensively around Europe always with acclaimed success.
Kaspar Fürstenau received his first musical instruction from his father, an oboist of the court orchestra of the Bishopric of Münster. After his father's death his employer, the prince bishop of Münster Maximilian Friedrich von Königsegg-Rothenfels, organized further training to him with the fagot teacher Bernhard Anton Romberg.
Fürstenau was booked in 1788 by Maximilian Friedrich's successor, Archduke Maximilian Francis of Austria, in whose court chapel he stayed. Then there the flautist Josef Antoni became among other things his teacher. From 1793 Furstenau was again sent by his employer on study trips to the courts of London, Paris and Vienna, to become a member of the court chapel of Augustus, Grand Duke of Oldenburg, who was for some time his teacher from 1794.