Brand loyalty is often perceived as synonymous with the flagship brand or even parent brand through consumer surveys. Yet, many successful parent brands have extended into new product categories or as line extensions within the same product category. Using panel data, we show that what appears to be brand loyalty is really line loyalty: consumers that are brand loyal at face value are truly loyal to a line extension within the brand, in some cases even more loyal than the flagship brand. The implication for marketing academics is that the construct of brand loyalty should be redefined for line extension loyalty, and that marketing managers should utilize line extension loyalty switching as measure for line extension success.