Wartsila Oyj Abp (Public, HEL:WRTBV) is a Finland-based global engineering company. It is operational through three principal divisions: Ship Power, which focuses on ship power solutions, including engines, generating sets, reduction gears, propulsion equipment, automation and power distribution systems, as well as sealing solutions for the marine industry; Power Plants, which offers power plants for the decentralized power generation market, including solutions for baseload power generation, grid stability and peaking, industrial self-generation, as well as for the oil and gas industry; and Services, which offers solutions that support the customers throughout the lifecycle of their installations, for ship machinery and power plants. The Company operates through a number of subsidiaries located in Europe, the Americas, Asia and Africa.

The core business of Wärtsilä is marine diesel engines, but its engines are also widely used in diesel-powered power plants. It employed 18,541 workers at the end of 2009.