This research examines how people respond when a commercial brand they identify with is threatened. Across four studies, the authors found that among participants who identified with a brand, a threat to the brand elicited the same responses as a threat to the self. Specifically, participants with low implicit self-esteem defended the brand when the self was activated, unlike their high implicit self-esteem counterparts. In addition, brand defense was reduced when individuals had the opportunity to affirm a valued aspect of their self-concept. These findings suggest that when a brand that people identify with is threatened, they may defend the brand to preserve the integrity of the self. More broadly, these findings are consistent with the notion that brands may be included into the extended self-concept, which supports William James's original ideas concerning the breadth and heterogeneity of the self.