The following is the order of battle of the Hellenic Army during the First Balkan War.
Greece, a state of 2,666,000 people in 1912, was considered the weakest of the three main Balkan allies, since it fielded the smallest land army and had suffered a humiliating defeat against the Ottomans 16 years before in the Greco-Turkish War of 1897.
Following the defeat, starting in 1904 and especially after the Goudi coup of 1909, serious efforts were undertaken to reorganize and modernize the Army. From 1911, this task was undertaken by a French military mission. The peacetime establishment of the Hellenic Army in 1912 comprised four infantry divisions (1st at Larissa, 2nd at Athens, 3rd at Missolonghi and 4th at Nafplion) newly reformed as triangular divisions, a cavalry brigade, six Evzones battalions, four field artillery and two mountain artillery regiments, one heavy artillery battalion and various support units, including two engineer regiments and an aircraft company. From 25 March 1912, Crown Prince Constantine assumed the position of Inspector-General of the Army, becoming its de facto commander-in-chief.
The army was still in the process of reorganization when the war began. With the escalation of the crisis between the Balkan states and the Ottoman Empire, on 29 September [O.S. 16 September] 1912, a general mobilization was declared. The existing units were brought up to full complement, and the 5th, 6th, and 7th infantry divisions were set up. This brought the peacetime establishment of ca. 25,000 men up to ca. 110,000. In contrast to pre-war planning, no army corps were established; instead, the divisions were directly subordinated to GHQ.