Market-level studies based on institutional theory have gained prominence in recent marketing research seeking to investigate legitimation dynamics. Although these studies have paid particular attention to how organizations build legitimacy in new markets, they have rarely explored legitimations strategies in mature markets, which mostly remain the prerogative of organizational theory. Such emphasis on new markets is thus limiting our understanding of legitimation dynamics in general and legitimacy maintenance in particular, especially since new and mature markets have different characteristics. When markets are well established, they tend to become the target of a growing number of contestations by actors seeking to introduce new societal issues. Once these issues have been institutionalized, organizations must address them to maintain their legitimacy. In this study, we investigate the discursive strategies used by the French carmakers when environmental considerations gained prominence between 2006 and 2008. In contrast to prior works in organizational theory which assume that organizations respond to institutional pressures in an undifferentiated way, our results show that organizations adopt differentiated legitimation strategies by adapting their discourse to their different stakeholders. Paradoxically, we find evidence of industry-wide isomorphism, where rather than developing idiosyncratic discourses, organizations adopt conventional discursive strategies. •We explore how firms can maintain their legitimacy in mature markets when confronted with societal shifts•We investigate how French carmakers discursively maintain their legitimacy when corporate environmentalism became a key issue•We show that firms use different discursive strategies depending on the stakeholders they target.•We demonstrate that these legitimation strategies are very similar across the three firms we examine.