Decarbonisation of the iron and steel (I&S) industry is crucial in the efforts to meet the EU GHG emission reduction objectives in 2030 … 2050. Promoting decarbonisation in this sector will necessarily require the identification, development, and diffusion of breakthrough technologies for I&S production. This paper uses an approach inspired by the Technology Innovation System (TIS) to analyse the development of technology in the EU I&S industry and identify potential avenues of its decarbonisation. We have described key elements of the TIS, analyse the functioning of these elements and their interactions in a more general context of innovation dynamics and policy design; The focus has been put on the role of actors and the identification of the main specific blocking and inducement mechanism in the TIS to better explain its functioning. Risks and uncertainties have also been discussed. We argue that deep decarbonisation in the I&S industry is feasible but its TIS requires firm support, mostly political, to finance intensive R&D and reduce the business risk. To this end, all actors shall support more effectively the invention and implementation of new radical production technologies. The recommendations are mostly addressed to politicians although stressing the importance of collaboration of all actors. •Problems, boundaries and difficulties in the I&S industry decarbonisation.•TIS structural components, links and interactions of I&S industry decarbonisation.•Mapping of functional patterns and evaluation of TIS functionality in I&S industry.•Blockades, incentives and innovation risks in the I&S industry decarbonisation.•TIS analysis as a tool for granting public funds for I&S projects.