Despite the global growth in the use of Voter Advice Applications (VAAs), which advise users on how similar their own policy views are to the policy positions of the political parties, there have been few field experiments that isolate the causal effects, at the individual and aggregate level, of VAA use on party support. Drawing on evidence from a field experiment in the deeply divided context of Northern Ireland, we find that provision of advice has an effect on users’ support for political parties at the individual level, and moreover that this advice leads to weaker ethno-national structuring of party support at the aggregate level. These results suggest that VAAs do have an impact on users, and in the deeply divided context can ameliorate the dominance of divide-based politics.