Valerius Harpocration was a Greek grammarian and lexicographer who lived during the 2nd century CE, a period of high Greek literary culture under Roman rule. The exact dates of his life are uncertain, but scholars generally place his work during the reigns of Hadrian or the Antonine emperors. His Roman family name, "Valerius," suggests he or his ancestors were granted Roman citizenship. He is sometimes identified with a sophist from Alexandria named Harpocration, though this connection is not definitive.

His professional role was part of a broader intellectual movement to preserve and explain classical Athenian language. His only known surviving work is the Lexicon of the Ten Orators, a dictionary explaining difficult words, historical references, and legal terms found in the speeches of ten canonical Attic orators like Demosthenes and Lysias. The original text is lost, and what survives is an abridged version.

The lexicon is considered a work of immense historical importance. According to modern scholars, it acts as a crucial bridge to the classical past, preserving fragments of knowledge from many earlier Hellenistic sources that are now lost. It became a standard reference, used extensively by later Byzantine scholars and encyclopedia compilers. For researchers today, it remains an indispensable tool for understanding the nuances of Athenian law, society, and oratory.