The Second Battle of Ypres was a battle of the First World War fought from 21 April – 25 May 1915 for control of the strategic Flemish town of Ypres in western Belgium, following the First Battle of Ypres the previous autumn. It marked the first mass use by Germany of poison gas on the Western Front. For the first time a former colonial force (the 1st Canadian Division) defeated a European power (the German Empire) on European soil, in the Battle of St. Julien and the Battle of Kitcheners' Wood.

Date Thursday 21 April – 25 May 1915 Location Ypres, Belgium Result Stalemate
Belligerents
French Empire France Algeria Morocco  British Empire  United Kingdom  Canada British India  Newfoundland  Belgium	German Empire
Commanders and leaders
Horace Smith-Dorrien (replaced by) Herbert Plumer (6 May 1915~) Arthur Currie Henri Gabriel Putz Théophile Figeys Armand De Ceuninck	Albrecht of Württemberg
Strength
2 French and 6 British divisions	7 divisions
Casualties and losses
70 000 killed, wounded or missing	35,000 killed, wounded or missing

Background

The Second Battle of consisted of six engagements:

• The Battle of Gravenstafel: Thursday 22 April – Friday 23 April 1915
• The Battle of Saint Julien: Saturday 24 April – 4 May
• The Battle of Frezenberg: 8–13 May
• The First Battle of Bellewaarde: 24–25 May
• The Battle of Hooge 30–31 July 1915 (first German use of flamethrowers)
• The Second Attack on Bellewaarde 25 September
• The Ypres salient followed the canal and then bulged eastward around the town of Ypres, Belgium. North of the salient the Belgian army held the line of the Yser and the north end of the salient was held by two French divisions.The eastern part of the salient was defended by one Canadian division and two British divisions. The II Corps and V Corps of the Second Army comprised the 1st, 2nd and 3rd Cavalry divisions and the 4th Division, 27th Division, 28th Division, 50th Division, Lahore Division and 1st Canadian Division.