Ktetor (Greek: κτήτωρ) or ktitor (Cyrillic: ктитор; Georgian: ქტიტორი kt’it’ori; Romanian: ctitor), meaning 'founder', is a title given in the Middle Ages in the Byzantine sphere to the provider of funds for construction or reconstruction of an Eastern Orthodox church or monastery, for the addition of icons, frescos, and other works of art. The Catholic equivalent of the term is donator. At the time of founding, the ktetor often issued typika, and was illustrated on frescoes ("ktetor portrait"). The female form is ktetorissa (Greek: κτητόρισσα) or ktitoritsa (Cyrillic: ктиторица).
The donator or renovator of churches are known as "second ktetor" or "new ktetor" (Serbian: Други ктитор, нови ктитор).
