Riau is a province of Indonesia, located in the center of Sumatra island along the Strait of Malacca. The provincial capital and largest city is Pekanbaru. Other major cities includes Dumai, Bagansiapiapi, Bengkalis, Bangkinang, Rengat and Siak Sri Indrapura.

Indonesian was based on the Riau version of Malay language.

Riau is one of the richest provinces in Indonesia. This province is rich with natural resources, particularly petroleumnatural gas, rubber, and palm oil. and

The province was once heavily forested lowlands, but with palm oil plantations and logging being major industries it is losing around 2,000 square km of forest per year. In 2005 the forest cover was down to 33% (or 27.000 square km) from 78% (or 64.000 square km) in 1982. Being a province with a predominantly low relief, the coastal regions are rapidly losing land to the ocean.

The Riau Islands were part of Riau until 2004, when they were made into a separate province.