- Desire to expand territory: Austria-Hungary was a declining empire, and its leaders saw war as a way to gain new territory and assert dominance in the Balkans.
- Reaction to Serbian nationalism: Austria-Hungary was concerned about the growing nationalist sentiment in Serbia, which threatened its control over Bosnia and Herzegovina.
Serbia
- Desire for independence: Serbia was a small, independent country surrounded by larger, more powerful empires. Serbian nationalists wanted to break free from Austrian and Ottoman rule and create a larger Serbian state.
- Support for Bosnian Serbs: Many Serbians lived in Bosnia and Herzegovina, which was annexed by Austria-Hungary in 1908. Serbia supported the Bosnian Serbs' desire for independence from Austria-Hungary.
- Serbian government and military intelligence sponsored the Black Hand, a terrorist organization that assassinated Archduke Franz Ferdinand.
Germany
- Desire for power: Germany was a rising industrial power that wanted to challenge the dominance of Great Britain and France.
- Support for Austria-Hungary: Germany had a strong alliance with Austria-Hungary and supported its efforts to suppress Serbian nationalism.
- Germany feared encirclement by France, Russia, and Britain
Russia
- Pan-Slavism: Russia was a Slavic country and saw itself as the protector of all Slavic peoples in Europe. This ideology led Russia to support Serbia, a Slavic country that was threatened by Austria-Hungary.
- Desire for access to the Mediterranean: Russia wanted access to the Mediterranean Sea through the Dardanelles, a strait controlled by the Ottoman Empire. Russia hoped to gain access to the Dardanelles by supporting Serbia in a war against Austria-Hungary and the Ottoman Empire.
- Fear of Austro-Hungarian expansion in the Balkans
France
- Revanchism: France had lost Alsace-Lorraine to Germany in the Franco-Prussian War of 1870 and wanted to regain these territories.
- Support for Russia: France had a strong alliance with Russia and supported its efforts to protect Serbia from Austria-Hungary.
- Fear of Germany increasing its power due to expansion
Great Britain
- Maintaining the balance of power: Great Britain had a long history of maintaining a balance of power in Europe to prevent any single country from becoming too powerful. Britain was concerned about Germany's growing power and supported Russia and France in an effort to contain Germany.
- Protecting naval supremacy: Britain's Royal Navy was the most powerful in the world and it was concerned about the threat posed by Germany's rapidly growing navy.
- Fear that Germany's support for Austria-Hungary and the Ottomans would increase its influence and power in Europe and the Middle East.