Factors that led to World War I are numerous, but the main concepts involved in all the specific events centered around nationalism, imperialism, and militarism.

Nationalist ideas were found strongly in the still subordinated ethnic groups of Austria, especially the Slavs, who wanted autonomy from the Habsburgs. This became especially pronounced in the assassination of Archduke Franz Ferdinand, an act by Gavrilo Princip and the terrorist group the Black Hand designed to stamp out anyone who might get in the way of the radicals. However, this assassination not only angered Austria, but its ally, Germany, and an ultimatum followed by war on Serbia was declared, with the Germans backing Austria. Serbia asked for help from the Russians, who in turn asked for help from the French, and this string of alliances sparked by the death of one man is often said to be the defining moment of the start of World War I.

Imperialistic forces clearly drove the countries to war, more and more with each passing year. The Fashoda and Moroccan Crises caused tension between countries as conflict arose in Africa, especially between Germany and France. Furthermore, as more African land was claimed by one country or another, there was competition for the little land remaining. This enmity between powers only became more pronounced as the other factors leading to the war came into play.

Militaristic causes of the war exist both in action and in the mindset of the people involved. Europe, especially Germany, had recently seen a string of successful wars that end in great amounts of profit, so it was natural to think that war could solve most anything. The inevitability of war at the sign of any sort of conflict was also ingrained into the masses' minds, making the people more eager to accept war as an option. The physical actions that came from this mainly consisted of the naval race between Britain and Germany. Britain had long ago established a competent navy, and Germany did not wish to be outclassed, so there was a demand for naval units to protect the new German colonies. With all the tension between countries as alliances were formed and armies built, it is difficult not to foresee a future war, and when it arrived, it certainly delivered.