This paper asks whether we can defend associative duties to our compatriots that are grounded solely in the relationship of liberal co-citizenship. The sort of duties that are especially salient to this relationship are duties of justice, duties to protect and improve the institutions that constitute that relationship, and a duty to favour the interests of compatriots over those of foreigners. Critics have argued that the liberal conception of citizenship is too insubstantial to sustain these duties — indeed, that it gives us little reason to treat compatriots any differently from how we treat foreigners, with all the practical consequences that this would entail. I suggest that on a specific conception of liberal citizenship we can, in fact, defend associative duties, but that these extend only to the duty to protect and improve the institutions that constitute that relationship. Duties of justice and favouritism, I maintain, cannot be particularised to one's compatriots.