Jean-Jacques Calvert (unknown – 1791) was a French member of the Templar Order.
As a known sympathizer of Élise de la Serre's claim on the leadership of the Order, Calvert and his father were expected to come to the Templar gathering called by Élise, in order to pledge their loyalty to her as the succesor of Grand Master François de la Serre in October 1789. Seeing the malaise of her host, Marquis de Pimôdan, Élise threatened him with her sword while questioning his motives.
Pimôdan told her that nobody arrived for the meeting, Calvert and his father were killed in an attack on their castle by sans-culottes, while the Marquis de Simonon and the Marquis de Kilmister were missing. This information prompted her to flee, as Pimôdan subtly informed her of killers waiting in the meeting room, under the orders from François-Thomas Germain, the self-proclaimed Grand Master of the extremist faction of the Templars.