The Graciloceratidae is a family of nautiloid cephalopods from the Middle and Upper Ordovician belonging to the Oncocerida, characterized by exogastric cyrtocones that expand slightly or moderately and have thin walled, orthochoanitic marginal or subventral, tubular siphuncles (Sweet 1964).

The Graciloceratidae was proposed by Rousseau Flower in 1950 and at that time placed in the Basslerocerida which has since been abandoned.

The Graciloceratidae are most likely derived from the Bassleroceratidae (Flower 1950) from which they differ primarily in having thin rather than thick connecting rings.

They are also the most likely source for the Oncoceratidae, Tripteroceratidae, and Valcouroceratidae (Flower 1950).

The Graciloceratidae contains five known genera, four of which are briefly described in the Treatise Part K, Nautiloidea-Oncocerida.