Brand extensions have the potential to both enhance liking of the brand extension and induce positive spillover effects on the parent brand. Such dual outcomes enhance the brand's growth potential. We propose and empirically demonstrate that three variables endemic to any brand extension decision (brand reputation, brand extension fit, brand extension benefit innovativeness) jointly impact these positive outcomes. For strong reputation brands, these dual outcomes are maximized when the brand extension is low in fit and offers innovative benefits because low fit motivates consumers to process innovative brand extension information more deeply. For weak reputation brands, these effects are maximized when the brand extension is high in fit and offers innovative benefits because high fit strengthens consumers' trust in the weak brand's ability to deliver promoted benefits. The results suggest two distinct brand growth strategies for strong and weak reputation brands respectively.