Prodicus of Ceos (Πρόδικος Pródikos, born c. 465 or 450 BC) was a Greek humanist of the first period of the Sophistic movement, known as the "precursor of Socrates." He was still living in 399 BC.

He came to Athens as ambassador from Ceos, and became known as a speaker and a teacher. Like Protagoras, he professed to train his pupils for domestic and civic affairs; but it would appear that, while Protagoras's chief instruments of education were rhetoric and style, Prodicus made ethics prominent in his curriculum. In ethics he was a pessimist. Though he discharged his civic duties in spite of a frail physique, he emphasized the sorrows of life; and yet he advocated no hopeless resignation, but rather the remedy of work, and took as his model Heracles, the embodiment of virile activity. The influence of his views may be recognized as late as The Shepherd of Hermas.

His views on the origin of the belief in the gods is strikingly modern. He held that man first worshipped those great powers which benefit mankind (comparing the worship of the Nile), and after these men who have rendered services to humanity were deified. Yet Prodicus was no atheist, for the pantheist Zeno spoke highly of him.

Of his natural philosophy we know only the titles of his treatises On Nature and On the Nature of Man. His chief interest is that he sought to give precision to the use of words. Two of his discourses were specially famous; one, "On Propriety of Language," is repeatedly alluded to by Plato; the other contained the celebrated apologue On the Choice of Heracles, of which the Xenophontean Socrates (Mem. ij. I, 21 seq.) gives a summary. Theramenes, Euripides and Isocrates are said to have been pupils or hearers of Prodicus. By his immediate successors he was variously estimated: Plato satirizes him in the early dialogues; Aristophanes calls him "a babbling brook"; Aeschines the Socratic condemns him as a sophist.