Theodosius of Sinai (Bulgarian: Теодосий Синаитски, Teodosiy Sinaitski; ? – March 1843) was a Bulgarian priest, writer and printer. He founded the first Bulgarian printing-house in Thesaloniki. Theodosius of Sinai is considered a Macedonian in the Republic of Macedonia.
Teodosius was born in the late 18th century in the town of Dojran, Ottoman Empire (today in the Republic of Macedonia). His birth name was Teohar (Bulgarian: Теохар). After he had finished Greek (language) school in Istanbul, Teohar went back to Dojran, where he got married and was later ordained a priest. The death of his wife however drove him into a pilgrimage to the Holy Land. In 1828 Teohar became a monk in Saint Catherine's Monastery and there he adopted the monastic name Teodosiues (Theodosiy in Bulgarian).
After returning to the Balkans, Theodosius was appointed a priest in "St. Minas" church in Solun (Thesaloniki) in 1831. While in Solun, he established the firsts printing house in Bulgarian (language) in 1838. Theodosius used the movable type printing press of Daskal Kamche from Vatasha. The moveable types of the press were crafted by a Russian immigrant type-founder. The first books, typed in Teodosius's printing house, were "Primary study through Slavonic-Bulgarian and Greek Orthodox morning prayers" („Началное учение с молитви утренния славяноболгарский и греческия“) and "Jewish ceremony and all of the harms, they've done" - an anti-Semitic lampoon, which was initially translated "to simple and plain Bulgarian language" by Nathanael Ohridski. In 1839 Teodosius typed his own "A Brief description of twenty monasteries that are situated in the Holly Mount Athos".
In 1839 Teodosius' printing-house was burned down, but it was soon restored with the finansical support of Kiril Peychinovich. Peychinovich's book Utesheniе Greshnim ("Solace of the sinner") was typed in the restored printing-house in 1840. Teodosius wrote аn introduction to the book, where he mentioned that the book was written by Kiril Peychinovich into "...the plainest Bulgarian language, spoken in Lower Moesia, and the region of Skopie and Tetovo...". There Teodosius also praised the Bulgarian language and compared it to a key, which can unlock the heart of the Bulgarian nation for the light of the truth.
In 1841 Teodosius typed a book, called "A book for studying three languages - Slavonic-Bulgarian, Greek and Karamanlian". The book was a Bulgarian-Greek-Turkish dictionary, designed to be of use for merchants.
In 1843 a fire destroyed Teodosius's printing house for a second and final time. Theodosius returned to Dojran, where he began working as a miller in his sons' water-mill. According to Arseniy Kostentsev, the usable remains of Theodosius' printing press were taken to the village of Vataša.
Theodosius died in an accident in March 1843. He was killed by a collapsed roof.
Nine years after Theodosius' death, the brothers Kiryak and Konstantin Darzhilovi opened a new Bulgarian-language printing press in Thessaloniki.