Despite the increasing importance of business-to-business loyalty, distributor loyalty (loyalty between a distributor and a supplier) has attracted very limited academic research. This these develops and test the construct of distributor loyalty through a synthesis of the related fields of customer loyalty and commitment. The thesis comprises seven chapters that outline three phases of research. Phase one involves the development of a provisional conceptual model through a combination of deductive and inductive approaches. The second phase describes the process and results of developing and testing measures for use in the model. The final phase outlines the empirical testing of the model on a sample of 151 respondents (27% response rate). The research uses a positivist ontological paradigm, and adopts a foundationalist epistemological perspective that means the majority of the data analyses are empirically based. Initial tests validated the conceptual model. However, refinement of the model resulted in improved performance, with the explanation of variance rising to 58%. The revised model comprises: a) three antecedents (trust, satisfaction and shared values); b) a moderating variable (contractual obligations); and c) a two-part dependent variable, where the behavioural component (repeat purchase behaviour [RPB]) mediates the relationship between the antecedents and the attitudinal component of the dependent variable (absolute attitude). Significant interactions were confirmed between: a) satisfaction and contractual obligations, b) trust and RPB, and c) shared values and RPB. The research represents an important start to the development of a robust theory of distributor loyalty in three ways: a) the related fields of customer loyalty and commitment have been synthesised to identify contributions to the conceptualisation of distributor loyalty; b) how distributor loyalty is perceived and conceived from a practical perspective has been determined by interviewing industry suppliers and distributors; and c) a conceptual model of distributor loyalty has been developed and empirically tested. The study concludes that further research into distributor loyalty is imperative if we are to build a comprehensive theory about the nature and components of distributor loyalty. Further research is especially important because it will investigate a research field that is in its infancy.