The authors tested predictions concerning the effects of respondents' identification with governing versus opposition political parties on feelings of political efficacy and trust, using data from the 1984 Canadian National Election Study. Dependent variables were political competence, perceived system responsiveness, and political trust, each measured federally and provincially. Respondents who supported the party in power scored significantly higher on perceived responsiveness and trust than those who supported opposition parties, although mainly at the provincial level. Whether respondents' preferred party was in power or not interacted with strength of party identification on the responsiveness and trust measures, both federally and provincially, as expected. Effects were much less pronounced for feelings of political competence. The authors suggest an interpretation to explain the weaker and inconsistent federal results. The article concludes with some observations concerning the relationship between partisanship, on the one hand, and efficacy and trust, on the other.