Ocellus of Lucania is a name attached to an ancient Greek philosophical treatise, but he is not considered a historical person. The name belongs to the Hellenistic period, likely from the 2nd or 1st century BCE, and is connected to the Pythagorean school of thought. The association with Lucania, a region in southern Italy linked to early Pythagorean communities, was part of a literary device to give the work an air of ancient authority.

The single surviving work attributed to him is On the Nature of the Universe. Modern scholars classify this as a pseudepigraphical text, meaning it was written by an unknown author who falsely credited it to an ancient Pythagorean sage. The treatise argues for the eternal and indestructible order of the cosmos. According to academic analysis, its ideas show a blend of Pythagorean, Aristotelian, and Stoic physics, reflecting the syncretic philosophy of the later Hellenistic era.

The historical importance of "Ocellus" lies entirely in this text's reception. Although the figure is likely fictional, the treatise was read and cited by later philosophers, including Neoplatonists and early Christian writers engaged in cosmological debates. It stands as a key example of how later thinkers used the names of revered ancient authorities to present and legitimize new syntheses of ideas.