Within the consumer behaviour literature, there has been little research on factors that influence customers' choices for organic foods. This study investigates three aspects of the Taiwanese organic food market. The first aspect considers how argument quality, source credibility, and social comparison affect consumer‐social venture identification. The second aspect examines how identity attractiveness, social media engagement, and self‐determination affect personal relevance. The third and final aspect investigates how consumer‐social venture identification and personal relevance influence customer citizenship behaviour. The results show that consumer‐social venture identification and personal relevance have significant and positive effects on customer citizenship behaviour. Furthermore, argument quality, source credibility, and social comparison all have significant and positive effects on consumer‐social venture identification. Finally, identity attractiveness, social media engagement, and self‐determination have significant and positive effects on personal relevance. This study makes three contributions regarding consumers' behaviour of purchasing organic foods. First, it explores whether consumer‐social venture identification and personal relevance are antecedents of customer citizenship behaviour. Second, it investigates whether argument quality, source credibility, and social comparison are antecedents of consumer‐social venture identification. Last, it examines whether identity attractiveness, social media engagement, and self‐determination are antecedents of personal relevance. The practical implications of this study indicate that firms must pay more attention to consumers' information search/sharing and perceptions of a credible environment for sharing information and their awareness about healthy items and personal images on social networking sites.