Athis-Mons was formed in 1817 by joining two villages, Athis (along the Seine) and Mons (on the adjacent plateau). Nowadays the lower area of the commune is commonly called Athis-Val.
A significant portion (approximately 80%) of Athis-Mons was destroyed during the Allied bombing raid of 18 April 1944. Approximately 300 people died and 4,000 people were left homeless. Athis-Mons had to be entirely rebuilt after the war.