Richarius of Celles (French: Riquier de Centule; Picard: Ritchier; c. 560 – April 26, 645 AD) was a Frankish hermit, monk, and the founder of two monasteries.

According to the vita written by Alcuin, Richarius gave shelter to two Welsh missionaries,[2] Caidocus and Frechorius, who were treated with great hostility by the local people who blamed the strangers for crop failure.

In 638, after some years in England, Richarius founded a monastery in his hometown in Ponthieu that was named Centule (or Centula, alteration of Latin Centum Turres: hundred towers).

Others also gave generously to Richarius's monastery, and he was able to use the money to help lepers and the poor and to ransom prisoners held by England.

In 950 Count Arnulf I transferred the bones to Montreuil, then to the Abbey of Saint Bertin in today's St-Omer; in 980 Hugo Capet returned them to St-Riquier.

The flower Erysimum barbarea (yellow rocket or wintercress) is associated with Richarius, whose feast day in the Roman Catholic Church is April 26.