The Greek-Serbian Treaty of Alliance marked a pivotal moment in Balkan politics and military strategy. Signed on June 1, 1913, the agreement between King Ferdinand of Bulgaria and King George I of Greece aimed to strengthen ties against the common threat of Bulgarian expansionism following the First Balkan War. The treaty outlined mutual support and cooperation between the two nations in the event of hostilities, reflecting their ambitions to secure territorial gains made during the previous conflict against the Ottoman Empire. The alignment of these two nations indicated a significant shift in power dynamics within the Balkans, where nationalistic fervor was growing. As the treaty was forged, tensions between Bulgaria and its former allies began to escalate, leading to rising hostilities. As a result, the treaty paved the way for the outbreak of the Second Balkan War, which was fueled by Bulgaria's dissatisfaction with the territorial divisions agreed upon after the First Balkan War.

The signing took place against the backdrop of a rapidly changing political landscape in southeastern Europe, characterized by rampant nationalism and militarization. The treaty served as a crucial component of the strategy for both nations, as they aimed to capitalize on the weakened state of the Ottoman Empire and expand their influence in the region. Ultimately, this alliance not only altered the course of the Second Balkan War but also had profound implications for subsequent geopolitical developments in Europe, including the lead-up to World War I.