Perceived discrimination (PD) is reliably and strongly associated with partisan identity (PID) among US immigrant minorities such as Latinos and Asian Americans. Yet whether PD causes PID remains unclear, since it is possible that partisanship influences perceptions of discrimination or that other factors drive the observed association. Here, we assess the causal influence of group-level PD on PID using five experiments with Latino and Asian American adults. These experiments varied in important ways: they took place inside and outside the lab, occurred prior to and during Donald Trump’s presidential campaign, and tested different manifestations of PD and partisan attitudes (total n = 2,528). These efforts point to a simple but unexpected conclusion: our experiments and operationalizations do not support the claim that group-targeted PD directly causes PID. These results have important implications for understanding partisanship among immigrants and their co-ethnics and the political incorporation of Latinos and Asian Americans.