This dissertation is empirically motivated by understanding the observed and ongoing green transformation of the maritime industry in Western Norway, a development that has had implications for both environmental protection, regional economic growth and job creation. Theoretically, the dissertation argues that the observed regional transformation processes should be analysed through an integration of three theoretical frameworks; 'Evolutionary Economic Geography' (EEG), 'Transition Studies' (TS) and 'Institutional Entrepreneurship Work' (IEW). As such, the dissertation argues that transformation is a complex phenomenon that requires co-evolution between several actors, technologies, policies and institutions, but also that these processes need to be embedded in evolving territorial contexts. Finally, these processes must be driven by purposeful actors aiming to change institutions to be more favourable for a green transformation. The dissertation approaches an integration between EEG, TS and IEW through engaging with three debates or 'areas of engagement' within these literatures. These include debates around how actors and agency affect institutional change processes, the role of territorial and multi-scalar dynamics, and the role of simultaneous and dynamically interacting dimensions of materiality, organization and discourse. Through these debates, the dissertation specifically argues for a new analytical framework which emphasises multi-actor institutional change (drawing on IEW), territoriality and multi-scalarity (drawing on EEG), and multi-dimensionality (drawing on TS), as well as the interplay between these elements. The theoretical discussion is illustrated, empirically, by an extensive case study of the green transformation of the Western Norwegian maritime industry. The dissertation is based on four qualitatively oriented papers, each of which contributes to the overall problem framings that it has sought to tackle. These papers focus on the following issues; Paper #1) how engineers perform multi-scalar institution changing practices in addition to technologist practices during processes of transformation; Paper #2) how the material, organizational and discursive dimension around a specific multi-scalar demonstration project (the actor-networks around and the materiality of a 'performing project enacting agency') have led to change in public ferry procurement on regional and national level; Paper #3) how achieving 'directionality' in cluster policy must recognise that regional clusters are embedded in different 'trinity' (materialityorganisation-discourse), sector and territorial/multi-scalar dynamics; and Paper #4) how green x List of papers This dissertation is based on the following papers: