Jacques Dumas (7 November 1908 – 21 July 1994), better known as Marijac, was a French comics writer, artist and editor.

Jacques Dumas was born in Paris in 1908. He started his career as a comics artist in te 1930s and used the pen name Marijac. His best known character in this period was the cowboy Jim Boum, which appeared in Coeurs Vaillants. During the war, he entered the Resistance and started the popular magazine Coq Hardi, where he created the series Les trois mousquetaires du maquis. The magazine existed from 1944 until 1963. His focus then shifted to the writing of comics for well known French artists like Raymond Cazanave (Capitaine Fantôme), Raymond Poivet (Colonel X), Dut, Mathelot, Étienne Le Rallic (Poncho Libertas), Kline, Trubert, and Calvo (Coquin). In later years, he continued to work as an editor at magazines aimaed at girls or younger children like Mireille, Frimousse and Nano et Nanette.

In 1979, he received the Grand Prix de la ville d'Angoulême, the highest comics award of France.