French medievalist and diplomatist
Olivier Guyotjeannin (born 13 March 1959, Suresnes) is a French medievalist and diplomatist. 
Career.
Olivier Guyotjeannin graduated as archivist-paleographer from the École Nationale des Chartes in 1981 with a thesis entitled "La seigneurie des évêques de Beauvais et de Noyon (Xe-début du XIIIe)" which earned him first place of his class. He was a member of the École française de Rome (1983–1986).
First a curator of archives in Saint-Pierre-et-Miquelon, he was later appointed at the Archives nationales in Paris.
In 1989, succeeding Robert-Henri Bautier, he was elected at the chair of institutions, archives and diplomatics of Middle Ages at the École des Chartes where he also taught medieval Latin.