Timolaus of Cyzicus was a historian from the city of Cyzicus, a Greek colony on the Sea of Marmara. He lived during the 4th century BCE, though no specific biographical details about his life or education survive.

He is known solely for a lost history titled Persica. The work is preserved only in fragmentary citations by later authors, such as Diodorus Siculus and Athenaeus, and dealt with Persian history and customs.

Timolaus represents a minor contributor to the Greek genre of Persian history. His Persica forms part of the Hellenistic historiographical tradition that documented the Achaemenid Empire for a Greek audience, and his fragments are occasionally cited as sources for Persian matters.