In conjunction with e commerce companies going in for expansion of diversified product offerings, extension of brand lines act as a crucial strategy to leverage on their established brand equity and capture the market share in the fast-growing market of quick commerce. Witnessing this extension, it’s imperative for the marketers to study the acceptance of brand extension. As Brand Resonance is the definitive level of consumer engagement with the brand, this study aims in understanding the effect of various elements of Brand resonance of the Parent brand on the acceptance of brand extension. Brand trust is considered to act as the mediator between brand resonance and acceptance of brand extension. Data collected from 520 consumers using structured questionnaire, was analyzed using regression model. The findings depict that Brand Attachment holds a pivotal position in influencing the acceptance of brand extension, while brand loyalty, Brand engagement and brand community are the subsequent important determinants. Furthermore, the strength of the relationship between brand resonance and acceptance of brand extension is contingent upon the brand trust between the line extension of the product/service and the parent brand. The mediation of brand trust between acceptance of brand extension and brand resonance was also examined. The implications of the study will equip the marketers to formulate strategies that increase the level of brand extension.