12 December

Western Front

 * Galicia: Austro-German counter-offensive from Hungary begins; the Dukla Pass carried and the Russians at Cracow threatened.

Southern Front

 * Serbia: Austrians utterly defeated, re-cross the Drina.
 * Bosnia: Vishegrad taken by Montenegrins.

Political

 * Great Britain: Mr. Balfour gives speech in Colston Hall, Bristol, in support of the War Office appeal for 3,000 more men.