The Campanha Ocidental micro-region (Microrregião de Campanha Ocidental, meaning the western fields in Portuguese) is a microregion in the western part of the state of Rio Grande do Sul, Brazil. The area is 31,125.429 km<sup>2</sup> making it the largest micro-region in the state nearly covering one-tenth of the entire state, much of the central and eastern portions remain underpopulated.
The microregion consists of the following municipalities: