In this article, we examine the current management of sexually transmitted infections (STIs), in the context of rising antimicrobial resistance (AMR), through the lens of 'treatment cultures'. Prevailing treatment cultures-including the prominence of syndromic care for STIs-foster certain possibilities and foreclose others, with important consequences for countering AMR. Drawing on qualitative interviews with STI professionals, experts and industry representatives, we unpack these stakeholders' accounts of STI treatment cultures, drawing out the importance of socio-historical (i.e. taboo and stigma), political-economic (i.e. perceptions of significance, profit-making and prioritisation) and subjective (i.e. patient contexts and reflexivity) dimensions therein. In developing this critical account of how treatment cultures are formed, reproduced and indeed resisted, we reveal how such discourses and practices render the reining in of AMR and shifting antibiotic use difficult, and yet, how productive engagement remains key to any proposed solutions. As such, the article contributes to our understanding of AMR as a highly diversified field, through our exploration of the bio-social dimensions of resistance as they relate to the case of STIs.