Sahaviriya Steel Industries PCL or simply SSI () is a Thai multinational steel-making company headquartered in Bangkok, Thailand. It was the largest steel sheet producer in Southeast Asia with annual capacity of 4 million tonnes of hot rolled coil, and the largest steel company in Thailand.
Sahaviriya Steel Industries has manufacturing operations in Thailand.
Following a period of difficult trading conditions the parent company was granted an application to wind up its UK business on 2 October 2015.