Promoted to Major General in 1912, during the First Balkan War he commanded the 4th Infantry Division, which played a crucial role in the Greek victory at the Battle of Sarantaporo by flanking the Turkish positions, as well as at the Battle of Giannitsa. After the capitulation of the VIII Ottoman Provisional Corps at Thessaloniki, Moschopoulos and his division were transferred to the Army of Epirus. On 4–6 January he substituted for Lt Gen Konstantinos Sapountzakis as commander of the Army of Epirus. During the second Greek assault against the Ioannina fortified zone on 7 January 1913, Moschopoulos commanded the right (eastern) flank, comprising the 4th Division and the Epirus Division. During the final Greek offensive, Moschopoulos commanded the Second Army Detachment on the army's left (western) flank, which executed the main attack against the forts around Ioannina.