Bruno Geisler (5 October 1857, Mittelwalde, Kr. Glatz, Silesia – 7 October 1945 Dresden) was a German ornithologist and bird illustrator.
In 1887, Bruno Geisler began collecting birds in Ceylon and Java with his brother Herbert. In 1890, they moved on to the then German colony New Guinea. Their bird specimens and some ethnographic material were mainly sold to the then zoological-ethnological-anthropological museum in Dresden (now Staatliches Museum für Tierkunde Dresden and Museum of Ethnology Dresden) and to the dealer Wilhelm Schlüter in Halle, Saxony-Anhalt. In 1893, Bruno Geisler became a curator and taxidermist in the Dresden museum.
The bird skins collected by Bruno and Herbert were studied by Adolf Bernard Meyer then a professor at the Dresden museum. Bruno was also a bird illustrator. He became also well known for the bird plates in The birds of Celebes and the neighbouring islands by Adolf Meyer and Lionel William Wiglesworth published in Berlin by R. Friedländer in 1898, Anton Reichenow’s Die Vögel Afrikas Vols 1-3 published by J. Neuman in Neudamm between 1897 and 1905 and in the new Naumann's, Naturgeschichte der Vögel Mitteleuropas published in 1900–1905.
Frogs Oreophryne geislerorum and Dendropsophus giesleri are named after him, the first together with his brother, Herbert Geisler. Also specific names of three birds honour him.