The Ragamuffin War (Portuguese: Guerra dos Farrapos), also known as the Ragamuffin Revolution or Heroic Decade, was a republican uprising that began in southern Brazil during the regency period, centered in the province of Rio Grande do Sul and, for a time, extending into neighboring Santa Catarina. It began on 20 September 1835, when rebel forces seized Porto Alegre, and soon turned into a wider confrontation between Brazil's imperial government and an opposition coalition led by influential regional leaders, such as Bento Gonçalves and Antônio de Sousa Neto, who proclaimed the secession of the province and the creation of the Riograndense Republic following the rebel victory at the battle of Seival in 1836.
The war is often situated within the broader political and institutional instability of Brazil's regency era, when numerous armed conflicts exposed the fragility of imperial authority and intensified disputes over the degree of autonomy between the Court and Brazil's provinces. In Rio Grande do Sul, the tensions unfolded over the region's economy, reliant on livestock and the production of jerked beef. Producers in Rio Grande do Sul complained that local jerked beef was burdened by high export and customs taxation and by import duties on salt, while Uruguay and Argentina benefited from more favorable tax treatment in Brazilian markets, making the local product less competitive within the country, which led to economic grievances with the Imperial government, but also due to a broader desire for greater autonomy and opposition to centralized control over the province. The revolution also influenced other rebel movements throughout the country, such as the Sabinada, in Bahia, in 1837, and the Liberal Rebellions in Minas Gerais and São Paulo, in 1842.