Th is paper contributes to the development of membership categorization and conversation analysis and, in turn, to their contribution to the gender and language field. Specifically, it shows how speakers invoke, produce, propose and sustain commonsense knowledge about gender categories. Drawing on a variety of spoken and written interactional settings, detailed analyses of a categorial practice are presented, which comprises three design features: description (e.g. ‘he offered me a lift’), categorization (e.g. ‘typical guy response’) and a common knowledge component (e.g. ‘y’know’). The analysis shows how these features are produced by one or more speakers, within or across a sequence of turns in particular action-oriented environments, and how they work to formulate idiomatic-style phrases that ‘package’ cultural knowledge (e.g. ‘that’s lads for you’). The analysis therefore reveals ‘what counts’ as gendered behaviour, through the activities and predicates that get tied, in situ, to gender categories. Through this categorial practice, speakers invite recipients to display recognition of, proffer as shared, collaboratively develop, challenge or resist the construction of a culture’s gender categories.