Otto Georg Dersch (born March 17, 1848, in Ortenberg, Hesse) was a German mathematician who worked in algebraic geometry. Dersch got his Ph.D. 1873 in GieÃÂen. He was teacher in GroÃÂ-Umstadt and Darmstadt and then director of a secondary school in Offenbach am Main, and then became director of a secondary school (Oberrealschule) in Darmstadt until at least 1915.