Timaeus the Sophist was a Greek grammarian and scholar active during the Roman Imperial period, with proposed dates ranging from the 1st to the 4th century CE. His epithet indicates he worked as a professional teacher. No details of his birthplace or biography survive.

His sole extant work is the Lexicon of Platonic Words, a glossary explaining difficult terms found in Plato’s dialogues. The text is preserved in a single 10th-century manuscript and was first published in 1833.

Timaeus’s lexicon is a valuable witness to later Platonic scholarship and ancient lexicography. It reveals which words were considered obscure by post-classical readers and contributes to our understanding of the scholarly reception of classical Athenian authors in the Roman era.