Valerius Harpocration was a Greek grammarian and lexicographer of the 2nd century CE. While his precise dates are unknown, his work is generally placed during the reigns of Hadrian or the Antonine emperors. His Roman family name indicates he or his forebears held Roman citizenship. He is occasionally associated with a sophist from Alexandria named Harpocration, but this identification is not certain.

His sole surviving work is the Lexicon of the Ten Orators, a dictionary explaining difficult words, historical allusions, and legal terms found in the speeches of ten canonical Attic orators, including Demosthenes and Lysias. The original text is lost; what survives is an abridged version.

The lexicon is a work of significant historical importance. It serves as a vital bridge to the classical past, preserving fragments of knowledge from numerous earlier Hellenistic sources that are otherwise lost. It became a standard reference work, used extensively by later Byzantine scholars and encyclopedists. For modern researchers, it remains an indispensable tool for understanding the nuances of Athenian law, society, and oratory.