PurposeThis paper aims to propose the concept of consumer legitimacy, develops scales to measure this concept and shows its utility and relevance in the international marketing field.Design/methodology/approachA four-step deductive approach (construct definition, item generation, scale purification and scale validation) is used to develop scales for three dimensions of consumer legitimacy, then a structural model of antecedents and outcomes of the construct provides validity for the developed scales.FindingsResults validate the developed scales with different multinational enterprise contexts across two countries. It is found that perception of social responsibility influences three dimensions of consumer legitimacy, both moral and cognitive legitimacy influence willingness to buy firm products, and moral legitimacy influences attitudes toward the firm.Practical implicationsAs a crucial resource, legitimacy can offer firms comparative advantages that lead to competitive advantages. The findings of this research provide a new perspective on how firms may measure, acquire and/or increase this resource.Originality/valueThis paper shifts the discussion of legitimacy to a key firm stakeholder that has been ignored in the literature: consumers. Thus, it implies that both researchers and practitioners should provide stronger consideration to the consumer role in granting legitimacy.