Brand extensions are a critical strategy for the introduction of new products, which are often prone to failure. The use of an established brand can help promote acceptance of the new product by reducing perceived risk, enhancing efficiencies in terms of distribution and promotion, and reducing overall costs associated with launching the new product. Previous research regarding brand extensions has shown that various factors influence success of brand extensions (e.g., marketing support and retailer acceptance). One of the most important factors driving brand extension success is the fit between a parent brand and its extension. A new marketing construct, emotional attachment to a brand, has recently been introduced to the brand extension literature. However, the role of consumers’ brand attachment, in terms of reactions to a brand extension has largely been ignored by researchers. The lack of research on brand extensions and brand attachment is somewhat surprising, given the considerable body of research findings that show consumers who are emotionally tied to a brand respond differently to that brand due to increased attachment. Building on this body of work, we propose that consumers who are emotionally attached to a brand will be less impacted by the degree of fit between the parent brand and its extension. In this research, we show that emotional attachment with a brand is an important factor underlying consumers’ responses to a brand extension. In particular, we explore the moderating role of brand attachment on consumers’ responses to extensions that vary in terms of fit with the parent brand. We also explore the process underlying observed effects. These issues are examined with an experiment regarding extensions for a real-world brand. Further, mediated moderation analyses indicate that the moderating effect of brand attachment is mediated by brand image fit, but not by product category fit. Implications of our findings for managers and researchers are also are provided.