This document provides a detailed technical description of the ENV-Linkages model. The OECD ENV-Linkages Computable General Equilibrium (CGE) model is an economic model that describes how economic activities are inter-linked across several macroeconomic sectors and regions. It links economic activity to environmental pressure, specifically to emissions of greenhouse gases (GHGs). The links between economic activities and emissions are projected for several decades into the future, and thus shed light on the impacts of environmental policies for the medium- and long-term future. In this paper specific attention is given to the equations that form the core of the model. The version of the model presented here is used for analysis carried out for the OECD Environmental Outlook to 2050 (OECD, 2012). An updated version of the model is expected to play a key role in the new CIRCLE project (OECD, 2013).