Jacques Ploncard (13 March 1910, in Chalon-sur-Saône – 20 February 2005), also called "Jacques Ploncard d'Assac", was a French writer and journalist and a political activist — he was, among other things, a member of the Parti Populaire Français.
Following the fall of the Vichy regime, he escaped to Portugal's Estado Novo in 1945, where he counselled Salazar.
He introduced Yves Guérin-Sérac, one of the co-founder of the OAS, to the PIDE.
After the April 1974 Carnation Revolution, he returned to France and collaborated on Présent, a newspaper which maintains loose links with Jean-Marie Le Pen's National Front.
Jacques Ploncard also wrote Doctrines of Nationalism.
His son, Philippe Ploncard, was also a member of the National Front.