Traditionally 'loyal' behaviour is viewed as something that must be earned (or bought) by marketers, i.e. a consequence of marketing actions (e.g. differentiation, service quality) and consumers' subsequent attitudinal preferences for particular brands. Yet loyalty is one of the most prevalent, marked characteristics of consumer behaviour. Instead of buying randomly, consumers show biased behavioural preferences, repeat-purchasing some brands over others. An alternative view is that loyalty is a natural human tendency in choice situations. In support of this view, this paper reviews a broad range of empirical evidence and the accompanying psychological explanations. Refereed/Peer-reviewed