The goal of this research is to develop and validate a multi-dimensional scale measure of brand fidelity. This paper reports the rigorous process of scale development, through two separate studies involving 592 US consumers. Study 1 involves scale item generation, content validation and scale purification, while Study 2 involves a two-wave data collection method, evaluating the refined brand fidelity scale within a nomological network of relationships. The results demonstrate the 20-item brand fidelity scale to have strong construct validity as a first-order reflective, second-order formative scale. The findings suggest that if consumers engage in the behaviours/cognitions (as defined within the brand fidelity scale), then consumer/brand relationships are likely to be stable and predictable; are likely to endure the ravages of time; and, importantly, are likely to remain monogamous. For practitioners, the overall brand fidelity score can be used to track brand performance over time and for industry benchmarking purposes. Additionally, the measured brand fidelity dimensions provide specific direction upon which remedial marketing action can be implemented.