The Serbian Revolutionary Organization (Serbian: Српска револуционарна организација, romanized: Srpska revolucionarna organizacija) or Serbian Chetnik Organization (Српска четничка организација, Srpska četnička organizacija) was a paramilitary revolutionary organization with the aim of liberation of Old Serbia (Kosovo and Macedonia) from the Ottoman Empire (in the vilayets of Kosovo, Manastir and Salonika).

Its Central Committee (Централни одбор, Centralni odbor) was established in 1902, while the Serbian Committee (Српски комитет, Srpski komitet) 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 [sr] (Српска акција у Македонији, Srpska akcija u Makedoniji).

Coincidentally, the Circle of Serbian Sisters or Kolo Srpskih Sestara, was also being formed in Belgrade in 1903. Although known for its charitable work, the Circle also helped the Chetnik Organization in the Ottoman-held territories of Kosovo and Macedonia by sending food and medical supplies, doctors, and nurses to aid the wounded and stricken as the Kosovo Maiden did in Medieval Serbia.

The Chetnik central committee had initially funded individual and small groups of hajduks (brigands), who were either self-organized or part of the Bulgarian revolutionary organizations in Macedonia (Supreme Macedonian-Adrianople Committee or Internal Macedonian Revolutionary Organization). These sought to protect the Slavic Christian population from zulum (atrocities, persecution). With the failed negotiations of a joint Serbian-Bulgarian action and growing nationalism within the Bulgarian committees, the Serbian committee decided to fully organize their own armed groups. The Central Committee sent the first two bands into Macedonia in 1904, which were exposed early and destroyed. The second wave proved more successful; however, hostility between the Bulgarian and Serbian committees began. Serb Chetniks thus fought the Ottomans, and Bulgarian and Albanian bands. Prominent guerrilla fighters include Jovan Babunski, Gligor Sokolović, Ilija Trifunović-Birčanin, Mihailo Ristić-Džervinac, Jovan Grković-Gapon, Vasilije Trbić, Garda Spasa, Borivoje Jovanović-Brana, Ilija Jovanović-Pčinjski, Jovan Stanojković-Dovezenski, Micko Krstić, Lazar Kujundžić, Cene Marković, Miša Aleksić-Marinko, Doksim Mihailović, Kosta Milovanović-Pećanac, Vojin Popović-Vuk, Savatije Milošević and Petko Ilić. After the proclamation of the Young Turk revolution in 1908 and the proclamation of the constitution, all of the brigands in Macedonia, including the Serbian Chetniks, put down their weapons; however, guerilla fighting soon continued, later merging into the Balkan Wars.

The Serbian–Ottoman War (1876–1878) and Russo-Turkish War (1877–1878) against the Ottomans motivated liberation movements among the people in Kosovo and Metohija and Macedonia (known at the time as "Old Serbia" or "southern Serbia"). Serbia sought to liberate the Kosovo Vilayet (sanjaks of Niš, Prizren, Skopje and Novi Pazar). The Serbian Army was joined by southern Serbs who made up special volunteer detachments, a large number being from Macedonia, who wanted to liberate their home regions and unify them with Serbia. These volunteers were infiltrated into the Kumanovo and Kriva Palanka districts. When peace was signed between the Serbs and Ottomans, these groups conducted independent guerrilla fighting under the Serbian flag, which they carried and flew far south of the demarcation line. The Serbian advance in Old Serbia (1877–78) was followed with uprisings for the Serbian cause in the region, including a notable one that broke out in the counties of Kumanovo, Kriva Palanka, and Kratovo. On 20 January, the Kumanovo Uprising broke out, spanning four months and ending with Ottoman suppression. The Ottomans retaliated against the Serb population in the Ottoman Empire. Because of the terror against the unprotected rayah (lower class, Christians), many left for the mountains, fled across the border into Serbia, from where they raided their home regions to revenge the atrocities carried out by the Ottomans.

After the war, the Serbian military government sent armament and aid to rebels in Kosovo and Macedonia. Christian rebel bands were formed all over the region. Many of those bands, privately funded and aided by the government, were established in Serbia and crossed into Ottoman territory. In that way, Micko Krstić formed a rebel band in 1879 in Niš, with the help of Nikola Rašić and the military government in Vranje. On 14 October 1880, an uprising broke out in the Kičevo-Poreče region, known as the "Brsjak Revolt". Serbia secretly and very carefully aided the Christians in the Ottoman areas, such as in the Brsjak Revolt; however, by 1881, the aid was stopped by the intervention of the government. The Ottoman army succeeded in suppressing the rebellion in the winter of 1880–81, and many of the leaders were exiled.

In 1886, the Association of Serbo-Macedonians was established.

The anti-Serb organization Society Against Serbs, established by Dame Gruev in 1897, had up until 1902 murdered at least 43 persons, and wounded 52 persons, who were owners of Serbian schools, teachers, Serbian Orthodox clergy, and other notable Serbs in the Ottoman Empire.