A certified environmental management system (EMS) is a coherent strategy for reducing your environmental impact, complying with legislation and setting continuous improvement targets in a systematic manner.

While ISO14001 is the most widely applied EMS in the world, the European Union has its own system, called EMAS, which goes beyond the ISO requirements.

Each EMS is built around a 'plan-do-check-act' principle, allowing companies to identify their environmental aspects and impacts, quantify them and plan for measures to improve performance. Since the mid-1990s, environmental management systems have become widely adopted by both public- and private-sector organisations, helping to reduce environmental risk and ensure legal compliance. An EMS requires active engagement with staff and stakeholders, and it demonstrates commitment and responsibility to clients, regulators and the public. 

Introducing an EMS may help a company achieve real cost savings in energy, water, waste, purchasing, and transport. Examples of economic benefits are shown in the study by Defra (2011), which found that EMS implementation typically took between 7 and 12 months. The majority of SMEs in the study implemented their EMS in this timeframe and achieved much higher cost savings at € 2 728 (£ 2 401) per million turnover than those that took either less or more time (average savings of less than € 568 (£ 500) per million turnover).