Sustainable energy advice is provided in a market in which sustainable energy (SE) consultancies, such as the Energy Research Institute of the Netherlands (ECN), provide SE research for policies and public policy-makers demand for research. However, the Sustainable Energy Advice Market (SEAM) and the way in which the SEAM’s impact on SE public policy-making can be measured, has not been researched in the scientific literature or understood within ECN Policy Studies. On the basis of a literature study, a report analysis and expert interviews, we developed an impact measurement framework. To start with, the approach consists of a market delineation approach in order establish which consultancies can have an impact on SE policy-making. Subsequently, three impact indicators are identified to qualify and quantify the impact of the advisories on SE policy-making processes. Two of the three indicators show usability, validity and reliability, whereas the third indicator needs development in further research. This research will contribute to the current scientific literature by providing impact indicators – an impact measurement framework - to describe and quantify the impact of SE consultancies on public policy-making. Further research could test the validity of the framework in related advisory markets.