Co-branding is a popular brand leveraging strategy, widely regarded as beneficial to allied brands. Despite its popularity in practice, there is a paucity of research on co-branding strategies in masstige marketing and luxury branding. Employing a quantitative research design via two survey-based experiments we examine the viability of co-branding versus downward extension on luxury consumers’ attitudes and purchase intent. Underpinned by Categorization and Information Integration theories, we find co-branding to be the more desirable masstige strategy in eliciting favorable consumer responses. Further, we show that co-branding is not detrimental to the prestige and desirability of the luxury brand partner, thus countering the narrative that democratization of luxury dilutes luxury brands’ appeal. Our research advances knowledge on luxury consumers’ evaluations of competing masstige strategies, the mechanisms underlying such evaluations, and the spillover effect of co-branding on luxury brands. We offer actionable implications for luxury brand managers desiring to expand into mass prestige markets.