The Republic of Negros (Spanish: República de Negros, Hiligaynon: Republica sang Negros) was a short-lived revolutionary republic, and later, administrative division, which existed while the Philippines was under Spanish and American sovereignty. It took its name from Negros Island.
From 3 November to 6 November 1898, the people of Negros rose in revolt against the Spanish authorities headed by politico-military governor, colonel Isidro de Castro. The Spaniards decided to surrender upon seeing armed troops marching in a pincer movement towards main city Bacolod. The revolutionaries, led by generals Juan Araneta, from Bago, and Aniceto Lacson, from Talisay, were actually carrying fake arms consisting of rifles carved out of palm fronds and cannons of rolled bamboo mats painted black. By the afternoon of 6 November, colonel de Castro signed the Act of Capitulation, thus ending Spanish colonial rule in Negros Occidental.
On November 27, 1898, the unicameral Chamber of Deputies (Spanish: Cámara de Diputados) met in Bacolod and declared the establishment of the Cantonal Republic of Negros (Spanish: República Cantonal de Negros). The Chamber of Deputies acted as a Constituent Assembly to draft a constitution.
When the invasion of the United States Army was looming, President Aniceto Lacson raised the American flag in the Casa Real to welcome the army as a friendly force. Despite the initial protest from the Negros Oriental deputies, the republic came under U.S. protection on April 30, 1899 as a separate state from the rest of the Philippine Islands and on the next day, the constitution was passed. On 22 July 1899, it was renamed the Republic of Negros, but on 30 April 1901, it was dissolved and annexed to the Philippine Islands by the United States, who retained control until the Japanese imperial occupation in the Second World War.