Lazar "Lazo" M. Kostić (Serbian Cyrillic: Лазар Лазо М. Костић; 15 March 1897 – 17 January 1979) was a Montenegrin Serb nationalist writer, economist, statistician and doctor of law.

[2] After the Axis invasion of Yugoslavia in April 1941, Kostić joined the German-appointed Commissioner Government, which was led by Milan Aćimović.

[3] The Commissioner Administration was "a simple instrument of the [German] occupation regime",[4] that "lacked any semblance of power".

[6] Kostić left Belgrade before its fall to the Yugoslav Partisans and the Soviet Red Army in October 1944.

[7] Following the war, he was a defender of the Chetnik movement of Draža Mihailović,[8] and wrote several books, advancing several controversial claims, including that Bosnian Muslims are Serbs,[9] and that war-time Serbia was free of antisemitism.