RWE AG (until 1990: Rheinisch-Westfälisches Elektrizitätswerk AG), is a German electric utilities company based in Essen, North Rhine-Westphalia. Through its various subsidiaries, the energy company supplies electricity and gas to more than 20 million electricity customers and 10 million gas customers, principally in Europe. RWE is the second largest electricity producer in Germany. RWE previously owned American Water, the United States' largest investor-owned water utility, but this was divested in 2008. Subsidiary RWE Dea produces some of the oil and gas its parent sells (annual production is around 2 million m³ of crude oil (about 365,000 boe) and 3 billion m³ of natural gas (about 18 million boe, 49,300 boe a day). It's the largest German investor in Egypt (RWE Dea and RWE Power do business in Egypt). Also RWE has begun building more wind farms, a renewable energy business.

The company was founded in Essen in 1898 as Rheinisch-Westfälisches Elektrizitätswerk Aktiengesellschaft (RWE). It first power station started operating in Essen in 1900.