Contemporary marketers build online brand communities to communicate with the organization’s social surroundings, yet there is a lack of understanding of how brand legitimization unfolds in these platforms. To understand how legitimacy is constructed and contested every day, the current study adopts a practice-theoretical lens and discourse analysis to investigate two online communities. The contribution of the study is twofold: First, the insights from the discursive praxis, online community posts, comments and reactions illustrate the connections between multiple levels of legitimization discourse. Second, this study builds a theoretical framework for legitimization practice. Individual perceptions, judgements of the texts and actions on them in the online community intertwine with the organizational and societal context shaping the legitimacy of the brand in the community and beyond. This practice supports or challenges the brand as an institution and may legitimize or delegitimize the brand.