Otto von Gerlach (born April 12, 1801, Berlin, Prussia [Germany]—died October 24, 1849, Berlin) was a Prussian Lutheran theologian and educator, younger brother of Leopold and Ludwig von Gerlach.
Educated at Berlin, Heidelberg, and Göttingen, he began lecturing at the University of Berlin in 1828; in 1834 he became pastor at the new St. Elisabeth Church in Berlin’s working-class district and brought a new kind of pastoral social work into the homes of the people. Eventually he became a court preacher and a regular professor at the university.