27 October

Western Front

 * Battle of the Yser: Belgians, with French aid, maintain unbroken the front Nieuport-Dixmude.
 * Neuve Chapelle taken by the Germans.
 * Germans pushed back east of Nancy.

Eastern Front

 * Poland: Russian victory along the line Petrokov-Radom.

Naval and Overseas Operations

 * South Africa: General Beyers defeated by General Botha at Commissie Drift, near Rustenburg.
 * HMS Audacious sunk by mine off the northern Irish Coast.
 * French liner Amiral Ganteaume sunk.
 * SMS Emden captures Japanese ship Kamasaka Maru.

Political

 * Portugal: Naval Reserves called up.