WW1 Allied Powers: The Nations That Won the Great War
The Allied Powers of World War I began as the Triple Entente and grew to include over 20 nations united against the Central Powers.
Learn more in our World War 1 Guide →
The Core Allied Powers
The Triple Entente (Original Three)
- Entered war: August 3, 1914
- Motivation: German invasion, reclaim Alsace-Lorraine
- Role: Western Front main battlefield
- Casualties: 1.4 million dead
- Entered war: August 1, 1914
- Motivation: Defend Serbia, compete with Austria-Hungary
- Role: Eastern Front, divided German forces
- Exit: 1917 (Russian Revolution)
- Casualties: 2+ million dead
- Entered war: August 4, 1914
- Motivation: German invasion of Belgium, treaty obligations
- Role: Western Front, naval dominance, global operations
- Included: Canada, Australia, New Zealand, India, South Africa
- Casualties: 900,000 dead (UK); 1 million+ (Empire total)
Major Allied Nations
- Switched sides from Central Powers
- Fought Austria-Hungary along Alps
- Promised territorial gains (not fully delivered)
- Entered after unrestricted submarine warfare, Zimmermann Telegram
- Fresh troops tipped the balance
- Wilson's Fourteen Points shaped peace
- Seized German Pacific colonies
- Limited European involvement
- Gained regional power
- Invaded by Germany despite neutrality
- Heroic resistance at Liège
- "Brave little Belgium" became rallying cry
- The war began over Austrian ultimatum to Serbia
- Suffered enormous casualties (25% of population)
Other Allied Nations
- Portugal (1916) — Colonial commitments
- Romania (1916) — Territorial ambitions
- Greece (1917) — After complex internal conflict
- Various Arab forces — Lawrence of Arabia's revolt
Why the Alliance Held
- Shared fear of German dominance
- Coordinated command (eventually)
- British financial support
- American industrial power
- Common democratic values (mostly)
Allied Strategy
- Stalemate on Western Front
- Gallipoli disaster
- Russian collapse
- Naval blockade of Germany
- Tank breakthrough tactics
- Fresh American forces
- German exhaustion