Constantin Sion (1796–1862) was a Moldavian chronicler.
The fifth son of court official (bașceauș) Iordache Sion and his wife Catrina (née Danu), he was the descendant of free peasants (răzeși). He was educated at Iași and knew Greek well. His positions included copyist at the treasury, messenger (ceauș) and guildmaster (staroste) at Focșani, estate manager in the Putna area and head of the Focșani public administration. His promotions ceased under Mihail Sturdza and Grigore Alexandru Ghica, leading to a feeling that he had been wronged. Together with his brothers Antohi and Costache, he composed the forged Izvodul lui Clănău or Chronicle of Huru. This was meant to prove the Sions' noble origin, and included an imaginary family tree. The brothers vehemently opposed the Union of the Principalities that occurred near the end of Constantin's life; the latter saw it as a "fools' project". His most noteworthy work, itself replete with fictitious or semi-fictitious genealogies, was Arhondologia Moldovei, composed between 1844 and 1856.