This International Standard describes the principles, requirements and guidelines for eco-efficiency assessment for product systems, including: the goal and scope definition of the eco-efficiency assessment; the environmental assessment; the product system value assessment; the quantification of eco-efficiency; interpretation (including quality assurance); reporting; critical review of the eco-efficiency assessment. Requirements, recommendations and guidelines for specific choices of categories of environmental impact and values are not included. The intended application of the eco-efficiency assessment is considered during the goal and scope definition phase, but the actual use of the results is outside the scope of this International Standard.