Emotional brand attachment is a key driver of long-term consumer–brand relationships, yet limited research has examined how different brand community structures foster such attachment. This study compares the effects of participation in small-group versus network-based brand communities and investigates the moderating role of regulatory focus. Using an online survey of 1,773 consumers from two Chinese-speaking markets, hierarchical regression analyses were conducted while controlling for product involvement, self-congruence, and public self-consciousness. The results show that brand community participation enhances emotional brand attachment, with participation in small-group communities exerting a significantly stronger effect than participation in network-based communities. Promotion-focused consumers develop stronger emotional attachment through small-group participation, whereas prevention-focused consumers exhibit weaker attachment in network-based communities. This study contributes to the literature by demonstrating how community structure embeds psychological distance, thereby extending construal-level theory, and by identifying regulatory focus as a key boundary condition shaping emotional outcomes in brand communities. The findings also offer practical insights for designing brand community strategies that align with consumers’ motivational orientations.