"Résistancialisme" (literally, "Resistance-ism") is a neologism, created in 1987 by the French historian Henry Rousso, to describe the myth which exaggerated the magnitude and importance of the armed resistance in German-occupied France during the Second World War. Rousso first put the argument in his 1987 work Le Syndrome de Vichy (The Vichy Syndrome) and re-iterated his argument in his 2001 book Vichy: L'Événement, la Mémoire, l'Histoire (Vichy: The Event, the Memory, The History). He argued that résistancialisme arose among amongst Gaullists and Communists soon after the war and became mainstream during the Algerian War. In particular, it was used to describe the belief that resistance was both unanimous and natural during the period, and justify the lack of historiographical interest in the role of French collaboration and the Vichy government.
Rousso emphasises that résistancialisme should not be confused with "Résistantialisme" (with a "t", literally "Resistant-ism"), a pejorative term coined by the Jean-Marie Desgranges to criticize individuals who retrospectively exaggerated or faked their own involvement in the wartime resistance in an attempt to enhance their own status, for instance François Mitterrand.