In a highly competitive banking environment, achieving customer loyalty is a key factor to enable banks to survive and grow. A rich literature has been developed on the determinants and consequences of customer loyalty, but there has been limited research investigating the relationships between loyalty components such as attitude, intentions and actual behaviour in retail banking. Furthermore, bank loyalty studies have often omitted the external environment, which is likely to moderate consumer attitudes and behaviour. The current empirical study of 1954 retail banking customers suggests a large proportion of the variance in behavioural intentions can be predicted, in particular by attitude, attitudinal differentiation and situational factors such as customer perceptions of competitors. However, these variables, in combination with satisfaction, behavioural intentions, switching costs and social norm, were revealed to be poor predictors of a number of measures of actual behaviour. Hence there is a large discrepancy in the ability to predict stated behavioural intentions and actual behaviour – approximately 60% of the variation in behavioural intentions can be explained, but a similar model explains only about 7% of the variation in actual behaviour. Of what can be predicted in actual behaviour, this study found that satisfaction with a bank’s technology is the strongest predictor of actual behaviour in terms of share of wallet.