Médaille commémorative de l'expédition du Mexique Ordre des Palmes Académiques Gustave Léon Niox ((1840-02-08)8 February 1840 – (1921-10-26)26 October 1921) was a French général, Governor of Les Invalides, director of the Musée de l'Armée, and a military historian.

Born in 1840 to Eutrope Léon Niox and Elisabeth Caroline Desrayaud, he entered the Ecole Spéciale Militaire de Saint-Cyr in 1856 to join the 10th Infantry Regiment, then l'École d'État-Major in 1859, training to command the 66th Regiment in January 1861.

He served with the Zouaves of the Imperial Guard and the second regiment of the Chasseurs d'Afrique, and was part of the French intervention in Mexico in the general staff, first in the topographical service, then later in the historical services.

He served in the Franco-Prussian War as a member of the general staff for the 6th Army of the Rhine, and was taken prisoner during the siege of Metz.

On his return in 1871 he was transferred to join the staff of l'Ecole d'État-Major, teaching cosmography, physical geography, and statistics.