Georg Mancelius (Latvian: Georgs Mancelis, born 24 June / 4 July 1593 in Grenzhof (now Mežmuiža in Augstkalne Parish), Courland; died 17 March 1654 in Mitau) was a Baltic German Lutheran theologian in what is now Latvia.
He wrote the first dictionary of the Latvian language.
From 1635 to 1636 he was Vice Rector of the University of Tartu and from 1636 Rector.