Oncoceratidae is a family of nauatiloid cephalopods in the order Oncocerida established by Hyatt, 1884, that range from the Middle Ordovician to the Upper Silurian.

(Flower 1950, 1976) Some Middle Ordovician oncoceratids such as Richardsonoceras and Oonoceras are, however, externally more similar to Bassleroceras than to Graciloceras.

Moreover, Richardsonoceras has been reported from the upper Lower Ordovician (Arenigian) of China, bringing its first appearance before the earliest known graciloceratids.

The Oncoceratidae through Oncoceras is thought to be the most likely source for the slightly endogastric Ordovician Diestoceratidae (Sweet 1964) and through the Early Silurian Amphycertoceras, for the Acleistoceratidae.

Neumatoceras; compressed brevicones with maximum height behind posterior end of body chamber, M-U Ord., N Am., Eu.