In recent decades there has been an exponential increase of activities in space, such that concerns regarding the long-term sustainability (LTS) of the space environment have called to action the need for sustainable and mitigating efforts to ensure that the benefits of space continue to be accessible and beneficial to all. In June 2019, the United Nations (UN) Committee on the Peaceful Uses of Outer Space (COPUOS) adopted twenty-one LTS guidelines. While the guidelines are not legally binding under international law, they reflect the latest global consensus on what responsible and sustainable space activities look like in practice. In parallel, private space actors have led the charge in the development of best practices. Based on sustainability ratings successfully used in other industries, the Space Sustainability Rating (SSR) was first conceptualized in 2016 within the World Economic Forum’s (WEF’s) Global Future Council on Space Technologies as a tool to assess and quantify sustainable design and operational decisions taken by operators. This article provides an overview of the design and development methodology of the SSR, and details how regulatory norms of behaviour and best practices have been incorporated into the SSR, allowing actors the opportunity to demonstrate their adherence to sustainability guidelines.