The Bio-LUSH project aims to demonstrate a reliable value chain that exploits the cell wall structure of underexplored plant resources in Europe, such as forest residues, marine plants and weeds, to extract high-quality fibers. By combining plant selection, traditional breeding, efficient valorization routes, and advanced fiber characterization, the project ensures the production of high-value fibers with short-term market potential. These fibers are directed towards sustainable bio-based products such as textiles, food packaging, and reinforced composites. The project contributes to retaining the value of the EU’s fibrous biomass and promoting the growth of the European fibrous bio-economy, revitalizing marginal and rural areas affected by desertification or socio-economic difficulties. The extended and circular use of plant biomass also contributes to decarbonization and reduced eutrophication.