Riau (disambiguation)
Riau is a province of Indonesia.
Riau may also refer to:
- Riau Islands, province of Indonesia
 - Riau Archipelago, part of Riau Islands Province
 - Riau-Lingga Sultanate, a Malay Sultanate that once governed Riau-Lingga Archipelago
 - Riau Residency, administrative unit of the Dutch East Indies
 - Revolutionary Insurgent Army of Ukraine (RIAU)