Do political parties shape citizens’ opinions to which they subsequently respond? Most works show that citizens are more likely to follow party cues and adjust their issue opinions. However, we know less about to what extent partisans follow their party and who among the partisans do so. Given the prevalence of increasing polarization in the Western democracies, I aim to answer the following question: When a political party takes a more extreme ideological stance, do party supporters follow by taking more polarized stances? I theorize that whether a partisan follows the party depends on (1) the extent to which she perceives the party’s shift and (2) her spatial location relative to the party. To test these expectations, I exploit a real-world sudden party polarization after a leadership change in the Labour Party of the United Kingdom in 2015 that shifted the party’s position to further left. Using British Election Study Internet Panel data, I find that Labour partisans become more left-wing. However, this is not the case for all Labour partisans. First, the more they perceive the party to have shifted to left, the more left-wing position they adopt. Second, only those that are located on the right of the party after the latter has moved further left follow the party. Furthermore, this effect is not short-lived and persists through 2017 and 2019 General Elections. These results provide insight into the conditional role of party identification in opinion formation, which has consequences for democratic representation.