["Psychology &Marketing, EarlyView. ", "\nABSTRACT\nThis research investigates how singlehood shapes brand attachment and identifies attachment avoidance as the central pathway. Across five studies (three of which were pre‐registered) in China and the United States (N = 2,015), single individuals showed weaker brand attachment than non‐singles because singlehood elevates attachment avoidance, which in turn reduces affiliative ties with brands. The effect remains robust after accounting for competing explanations. We also document boundary conditions that attenuate this spillover: secure‐attachment priming lowers attachment avoidance, materialism redirects attachment motives toward possessions, and cultural context moderates the effect—where societal acceptance of singlehood is higher (more individualistic settings), the negative impact on brand attachment is weaker than in family‐centered cultures. Theoretically, we distinguish assimilation from compensation mechanisms of affect regulation. Departing from prior work that emphasizes compensatory attachment, our findings highlight an assimilation process through which attachment avoidance suppresses relational engagement with brands, extending attachment theory from interpersonal bonds to consumer–brand relationships.\n"]