Julius Friedrich August Bahnsen (March 30, 1830 – December 7, 1881) was a German philosopher.
Bahnsen is usually considered the originator of characterology and a real-dialectical method of philosophical reflection which he laid down in his two-volume Contributions to Characterology (1867) and developed forth with his following works, amongst others his opus magnum The Contradiction in the Knowledge and Being of the World (1880/82).