A B S T R A C T In this study, we present and apply an interdisciplinary approach that systematically draws qualitative insights from socio-technical transition studies to develop new quantitative scenarios for integrated assessment model-ling. We identify the transition narrative as an analytical bridge between socio-technical transition studies and integrated assessment modelling. Conceptual interaction is realised through the development of two contrasting transition narratives on the role of actors in meeting the European Unions' 80% greenhouse gas emission re-duction objective for 2050. The first transition narrative outlines how large-scale innovation trajectories are driven by incumbent actors, whereas the second transition narrative assumes more 'alternative' strategies by new entrants with strong opposition to large-scale technologies. We use the multi-level perspective to draw out plausible storylines on actor positioning and momentum of change for several technological and social niche-innovations in both transition narratives. These storylines are then translated into quantitative scenarios for integrated assessment modelling. Although both developed transition pathways align with the European Union's low-carbon objective for 2050, we find that each pathway depicts a substantial departure from systems that are known to date. Future research could focus on further systematic (joint) development of operational links be-tween the two analytical approaches, as well as work on improved representation of demand-oriented solutions in techno-economic modelling.