Vojislav Tankosić was a Serbian military officer, vojvoda of the Serbian Chetnik Organization, major of the Serbian Army, and member of the Black Hand, who participated in the May Coup and was accused of involvement in the Assassination of Archduke Franz Ferdinand.

The Serbian Revolutionary Organization or Serbian Chetnik Organization was a paramilitary revolutionary organization with the aim of liberation of Old Serbia from the Ottoman Empire. Its Central Committee was established in 1902, while the Serbian Committee was established in September 1903 in Belgrade, by the combined Central Boards of Belgrade, Vranje, Skopje and Bitola. Its armed wing was activated in 1904. Among the architects were members of the Saint Sava society, Army Staff and Ministry of Foreign Affairs. It operated during the Struggle for Macedonia, a series of social, political, cultural and military conflicts in the region of Macedonia; its operations are known as Serb Action in Macedonia.