cis-Polybenzobisoxazole (PBO) fibres exhibit outstanding mechanical, thermal and electrical properties but poor interfacial adhesion to a variety of resin systems. In order to improve the interfacial adhesion between PBO fibres and a model resin system, a PBO end-capped benzocyclobutene-PBO dope blend was prepared to chemically couple the fibre to the matrix resin. It was demonstrated that a 75% increase in interfacial adhesion was achieved as measured using the microbond test method without sacrificing any of the other desired properties of the fibre. The process of dope preparation, fibre spinning and sample testing are described in detail.