René Cagnat (10 October 1852 – 27 March 1937) was a French historian, a specialist of Latin epigraphy and history of North Africa during Antiquity.

His most lasting achievement was the creation in 1888 of the journal L'Année épigraphique, in which epigraphy reports, previously widely dispersed, were collected and published.

At the request of Theodor Mommsen, he studied, first with Johannes Schmidt then with Hermann Dessau, these inscriptions for the Corpus Inscriptionum Latinarum.

Between 1906 and 1927, Cagnat contributed to the publication of Inscriptiones Graecae ad res Romanas pertinentes (collection of Greek inscriptions on topics related to the Roman Empire).

In 1887, Cagnat was appointed a professor at the Collège de France, where he succeeded Desjardins at the chair of Roman epigraphy and antiquities.