Of all the Byzantine icons that survive in the world, over half of them are at Saint Catherine’s Monastery. This is due to the dry and stable climate, to the uninterrupted history of the monastery over the course of seventeen centuries, and to the vigilant care and devotion of the monks of Sinai. The most notable are panel icons from the 6th and 7th centuries executed in the encaustic technique, where wax is used as the medium for the pigments.

The most celebrated icon is the Sinai Christ. An icon of the All-holy Theotokos depicts her on a throne, holding the Christ child. To her left is Saint George, and to her right, Saint Theodore. Above, two angels look up into the heavens, from which a halo may be seen, and a hand extended in blessing. An icon of Saint Peter shows him in three-quarters view, his head slightly turned. He is holding the keys of the kingdom of heaven, and a staff surmounted by a cross. Above him are three medallions, depicting Christ, the Virgin Mary, and a third figure portrayed as a youth, perhaps Saint John the Theologian. The pre-iconoclastic icons at Sinai survived because Sinai was already at that time under the rule of the Moslems, and thus out of reach of the Iconoclast Emperors. Some scholars have speculated that icons were sent to Sinai for their safekeeping during this period.

There are numerous icons from the Comnenian dynasty. These are renowned for their hieratic quality, and distinctive polished gold haloes. The monastery preserves a number of vita icons, in which the principal figure of the saint, depicted in the centre of the panel, is surrounded by smaller icons depicting his life. These are some of the earliest vita icons in the world.

The monastery also possesses noteworthy examples of icons from the Palaeologan era, which are more painterly and more stylized, and significant examples of the Cretan school, where great attention was paid to details, and where the transition from light to dark in the modeling of flesh tones became more heightened. The monastery also possesses important examples of Russian icons from more recent centuries.

Many of these icons were brought to the monastery as gifts, but numerous icons were also executed at Sinai, and there is a distinctive Sinai school of iconography discernible in earlier centuries.