This study examines the impact of conspicuous consumption on environmentally sustainable fashion brands (ESFBs). Most previous studies have been limited to environmental perspectives; however, research on environmental behavior by conspicuousness has been lacking. This study views the brand as a tool for revealing oneself and examines the moderator brand–self-connection. It utilized a structural equation model with 237 valid questionnaires. Its findings are as follows: (1) Conspicuous consumption, fashion trend conspicuousness, and socially awakened conspicuousness positively affect the word-of-mouth (WOM) marketing of ESFBs. (2) Environmental belief is fully mediated by the environmental norm (EN) and does not directly affect WOM. (3) The more consumers are consistent with ESFBs, the stronger their WOM marketing. They are moderated only by the EN and socially awakened conspicuousness. (4) A higher fashion trend conspicuousness is associated with increased WOM marketing, indicating that such brands are frequently used as a method of self-expression. This study highlights consumers’ socially awakened conspicuousness and fashion trend conspicuousness in relation to ESFBs and discusses some implications.