Nikolaos Vlachopoulos (Greek: Νικόλαος Βλαχόπουλος; 1868–1957) was a Hellenic Army officer who rose to the rank of Lieutenant General.

He participated in all the Greek wars of the early 20th century, and served twice as chief of the Hellenic Army General Staff, in 1922–24 and in 1927–28.

Promoted to major general in 1919, he assumed command of the Athens-based 2nd Infantry Division and led it during the Greek participation in the Allied intervention in Ukraine against the Bolsheviks.

On his return he was appointed as the first military governor of Smyrna following its occupation by Greece, and remained in Anatolia until dismissed from the army following the monarchist victory in the November 1920 elections.

He also wrote an artillery manual for the Military Academy and translated into Greek the book of the German field marshal Colmar Freiherr von der Goltz on the Greco-Turkish War of 1897.