Nicias of Nicaea was a Hellenistic historian of the 3rd century BCE, originating from the city of Nicaea in Bithynia. Beyond this geographic association, no details of his life are preserved.

His sole known work is a History of the Successors, a lost prose account of the wars following Alexander the Great’s death. The surviving fragments indicate it focused on the conflicts among Alexander’s generals, the Diadochi.

Nicias is a minor figure whose significance lies in representing the proliferation of local historians in Hellenistic Asia Minor. His work was used as a source by the later historian Memnon of Heraclea, through whom Nicias contributed to the transmission of historical details about the early Hellenistic period in Bithynia.