Consociational democracy is commonly discussed through the assumed premise of co‐ethnic group representation whereby representatives are institutionally incentivized to represent co‐ethnic interests. However, little attention has been paid to the process of group representation in consociations, in particular the link between descriptive and substantive ethnic group representation. This article considers representative claim‐making on behalf of ethnolinguistic groups in the Brussels Capital Region (Belgium), which is politically divided into Dutch and French speakers. Brussels constitutes an interesting case, because while we would expect co‐ethnic claim‐making to be the norm, Brussels MPs also receive electoral incentives to make representative claims on behalf of the other ethnolinguistic group (i.e., cross‐ethnic claim‐making). Based on a quantitative analysis of representative claims in parliamentary documents (2009–2019) from the Brussels Parliament, we find that cross‐ethnic claim‐making remains limited compared to co‐ethnic claim‐making, and that Dutch speakers and ethnic outbidders are more likely to speak on behalf of co‐ethnics.