15 September

Western Front

 * The Aisne: Heavy German counter-attacks: Soissons shelled.
 * Forest of Argonne: Germans begins slow advance, continued to 21 October.
 * Arras occupied by Germans.

Eastern Front

 * East Prussia: Russians prepared to resist German pursuit on the Niemen.
 * Bukovina: Russians occupy Czernowitz.

Southern Front

 * Serbia: Austrians pushed back across the Drina save at a few points: their second invasion of Serbia suspended.

Naval and Overseas Operations

 * South Africa: Meeting of rebels at Potchefstroom.
 * General Delarey accidentally shot on his way thither with General Beyers.