The 1917 French Army mutinies took place amongst French Army troops on the Western Front in Northern France during World War I. They started just after the unsuccessful and costly Second Battle of the Aisne, the main action in the Nivelle Offensive in April 1917. The new French commander of the armies in France, General Robert Nivelle had promised a decisive victory over the Germans in 48 hours; morale in French armies rose to a great height and the shock of failure soured their mood overnight.

The mutinies and associated disruptions involved, to various degrees, nearly half of the French infantry divisions stationed on the Western Front. The term "mutiny" does not precisely describe events; soldiers remained in trenches and were willing to defend but refused orders to attack. Nivelle was sacked and replaced by General Philippe Pétain, who restored morale by talking to the men, promising no more suicidal attacks, providing rest and leave for exhausted units and moderating discipline. He held 3,400 courts martial in which 554 mutineers were sentenced to death and 26 were executed.

The catalyst for the mutinies was the extreme optimism and dashed hopes of the Nivelle Offensive, pacifism (stimulated by the Russian Revolution and the trade union movement) and disappointment at the non-arrival of American troops. French soldiers on the front had unrealistically been expecting US troops to arrive within days of the U.S. declaration of war. The mutinies were kept secret from the Germans and their full extent was not revealed until decades later. The German failure to detect the mutinies has been described as one of the most serious intelligence failures of the war.