Praxiphanes of Mytilene was a philosopher and scholar of the late 4th and early 3rd centuries BCE, during the early Hellenistic period. He was a member of the Peripatetic school, founded by Aristotle, and was a student of Theophrastus, who led the school after Aristotle. Ancient sources also record that he taught the poet Aratus. Beyond these associations, the details of his life are not well known.

His writings, which are all lost and known only through references by later authors, focused on literary criticism. He is credited with a treatise On Poems, which discussed different genres of poetry and is considered one of the earliest systematic works of literary criticism. He also wrote a dialogue titled On History, which was structured as a conversation between the historian Thucydides and the poet Euripides. Other works addressed topics related to poets and sophists.

According to modern scholars, Praxiphanes is significant for helping to expand Aristotelian philosophy into the study of literature and language. His work represents an early Peripatetic engagement with defining and comparing literary forms like poetry and history. Although his texts do not survive, he was cited by later grammarians and writers like Cicero, indicating that his ideas contributed to ongoing debates about literary style and genre in the ancient world.