Paper did not exist in the ancient Mediterranean world. Instead, people wrote on an enormous variety of other materials. While almost every substance imaginable has been used as writing material at one time or another, this article focuses on the common ones. First, it considers papyrus since the overwhelming majority of ancient texts are written on this material. It discusses parchment, ostraca, and wooden tablets which receive considerable attention. It also discusses linen (e.g., mummy bandages) and stone (mainly Coptic limestone ostraca inscribed with ink). Looking at Coptic documentary texts, which extend past the end of antiquity, ostraca are the most important medium (47.5%), while papyrus is second (40.5%). Limestone accounts for 10.5%, while skin (leather/parchment), paper, and wood represent less than 1% each.