Polybius of Sardis was a Greek rhetorician and sophist active during the 1st and 2nd centuries CE. A native of Sardis in Lydia, his career belongs to the Second Sophistic, a movement characterized by a revival of Greek oratory and Atticism.

As a professional sophist, he would have delivered declamations on historical and mythological themes for public display and instruction, though no details of his education or patronage survive. No specific works by Polybius are named or described in extant sources, and his writings are presumed lost.

His significance lies as a minor, attested example of the provincial intellectual elite within the Roman Empire. Figures like Polybius participated in the pan-Hellenic culture of rhetorical performance, contributing to the maintenance of Greek identity and paideia under Roman rule. His inclusion in historical lists indicates contemporary recognition, though he did not achieve the fame of leading Second Sophistic orators.