Otto Karl Alexander Mejer (27 May 1818, Zellerfeld – 24 December 1893, Hanover) was a German canon law specialist and church historian.
While a student in Berlin, he was deeply influenced by the teachings of Friedrich Carl von Savigny.
Not long after graduation, he became a lecturer at Göttingen, and in 1845/46 took an extended study trip to Rome.
[1] In 1847 he became a full professor of law at the University of Königsberg, which was followed by professorships at Greifswald (1850) and Rostock (1851).
In 1874 he returned as a professor to Göttingen, where he taught classes until his retirement in 1883.