This chapter summarizes the research on the development of compartmented fibres for self-healing fibre reinforced polymer composite applications. The compartmented fibre concept combines the advantages of both capsule based and hollow fibre based extrinsic healing strategies: the mesoscopic fibre geometry facilitates the spatial distribution of the healing agent in a fibre reinforced composite while the microscopic vacuoles within the fibre filled with a healing agent allow for very local and distributed healing events. Fibres containing the healing agent discretely distributed along the fibre can be obtained from an alginate emulsion containing the healing agent as the dispersed phase spun into a coagulation bath. The vacuole characteristics can be tuned by adjusting the emulsion and the spinning conditions. Fibres containing the self-healing agents have been embedded in both thermoplastics and thermosets and demonstrated the high potential of this alternative concept for self-healing composites.