RIAS can stand for one of the following:
- Recording Industry Association (Singapore)
- Regulatory Impact Analysis Statement, a description of the impact of new Canadian federal regulations
- Remote Infrared Audible Signage
- "Research Institute for Advanced Study", the former research facility created by the Glenn L. Martin Company
- Reynolds Intellectual Assessment Scales, an intelligence test
- Rias, the plural of Ria, a lower river valley submerged by the sea
- Rich Internet Applications, kinds of Web applications
- Royal Incorporation of Architects in Scotland, a professional body.
- Rundfunk im amerikanischen Sektor (Broadcasting in the American Sector), a radio and television station in West Berlin
- Runway Incursion Alert System