The chartoularios or chartularius (Greek: χαρτουλάριος), Anglicized as chartulary, was a late Roman and Byzantine administrative official, entrusted with administrative and fiscal duties, either as a subaltern official of a department or province or at the head of various independent bureaus.
The title derives from Latin chartulārius from charta (ultimately from Greek χάρτης chartēs), a term used for official documents, and is attested from 326, when chartularii were employed in the chanceries (scrinia) of the senior offices of the Roman state (the praetorian prefecture, the officium of the magister militum, etc.). Originally lowly clerks, by the 6th century they had risen in importance, to the extent that Peter the Patrician, when distinguishing between civil and military officials, calls the former chartoularikoi. From the 7th century on, chartoularioi could be either employed as heads of departments within a fiscal department (sekreton or logothesion), as heads of independent departments, or in the thematic (provincial) and tagmatic administration, although the occasional appointment of chartoularioi at the head of armies is also recorded. The ecclesiastic counterpart was called a chartophylax, and both terms were sometimes used interchangeably.