Ștefan Foriș (; born István Fóris, also known as Marius; 9 May 1892 – summer 1946) was a Hungarian and Romanian communist journalist who served as general secretary of the Romanian Communist Party (PCR or PCdR) between December 1940 and April 1944. Born a Transylvanian Csángó and an Austro-Hungarian subject, he saw action with the Hungarian Landwehr throughout World War I.
While training in mathematics at Eötvös Loránd University, he affiliated with the Galileo Circle and, moving to the far-left, entered the Hungarian Communist Party in late 1918. During the brief existence of a Hungarian Soviet Republic, he joined the war against Romania (1919), but subsequently opted to settle in the Romanian Kingdom, at Brașov. Foriș emerged as a local leader of the Socialist Party, largely failing at convincing his subordinates to join the PCR upon its creation (1921).
He took up underground work even before the PCR was formally outlawed, while establishing his public profile as an accountant and a correspondent for moderate left-wing newspapers—including Adevărul and Facla. From his new home in Bucharest, Foriș presided upon two PCR front organizations, including the Red Aid's local branch and the Peasant Workers' Bloc. He was caught up in the repression of the mid-to-late 1920s, but escaped to the Soviet Union before being sentenced.
He was a Comintern cadre to 1929, choosing to return to Bucharest in 1928, after a general amnesty.