Ji-Paraná (sometimes spelled Jiparaná) is the second most populous city in the Brazilian state of Rondônia. Its population was 116.587 (2010) and its area is 6,897 km². The city is divided by the Ji-Paraná River.
Located in central Rondônia, the city attracted many settlers from the 1970s onward. As a result of corruption, lawlessness and a general lack of regulation, Ji-Paraná has been at the centre of Rondônia's extreme deforestation, which today extends up to the border with Bolivia. The area between Ji-Paraná and Porto Velho, the regional capital 373 km away, is now largely deforested. The deforestation expands along smaller illegally built roads stemming from the BR-364 highway.
Jesualdo Pires Ferreira Junior is the city's current mayor, his term expires in 2016.