This research proposes an augmented conceptual model which traces the role of perceived brand trustworthiness (PBT) and emotional attachment to the brand (EAB) on the formation of brand immunity (BI) and tests it for the moderating influence of generational cohort membership. Test results of the model with an Indian sample of Gen Y and Gen X consumers validate all the propositions except one, thereby enriching BI theory in the backdrop of generational differences. We contribute to the branding literature by showing that the proposed model holds good for consumers belonging to both Gen X and Y, though the strength of the relationships varies based on the specific cohort membership. Gen Y falls slightly short of the overall strength exhibited by Gen X, thereby supporting the moderating influence of cohort difference. We also demonstrate the partially mediating role played by EAB in the formation of BI originating from PBT. Our findings provide brand custodians with useful insights to make better decisions taking into cognizance the psychological process behind how Gen Y and X consumers develop BI. © 2017 Macmillan Publishers Ltd.