Customer advocacy involves strong and passionate recommendations being made by customers. However, there is little published research indicating how and why customers act as advocates for service providers for whom they have strong feelings. The primary aim of this research is to investigate the characteristics of and the contributors to customer advocacy. The research project consists of three studies. Study 1 conceptualizes and develops a scale of customer advocacy based on both qualitative and quantitative research. Results suggest that customer advocacy is a second-order construct characterized by two dimensions - spontaneous endorsement and proactive promotion. The scale exhibits solid reliability, predictive validity and discriminant validity from the theoretically-related measure of general positive WOM. Study 2 draws on self-determination theory to examine the determinants and contingent conditions of customer advocacy. Structural equation modelling analysis indicates that advocacy is largely driven by evaluative and motivational antecedents, while the effect of these antecedents on advocacy is moderated by situational and relational factors. In addition, the determinants of customer advocacy differ in their impact on general positive WOM. For example, the relative importance of the motivational dimensions is stronger in advocacy than in general positive WOM. Study 3 profiles customers with varying degrees of strength of recommendation across a range of demographic, consumer-related and psychographic factors. It is found that customers who are female, heavy users and referred by other customers are more likely to produce the strongest level of recommendation. Advocates and general positive WOM communicators tend to have a greater level of agreeableness and risk-aversion. Further, latent class analysis identifies four segments of customers. These customer segments display varying degrees of recommendation strength and other attitudinal/behavioural loyalty outcomes with unique demographic characteristics. This research appears to make the first attempt to conceptually delineate customer advocacy and to reveal the contributing influences behind the higher levels of recommendation strength. It should assist service managers in prioritizing their targeting of customers and their service improvement efforts in exploiting the power of customer recommendation as an important component of customer strategy.