Substantial research has been done in recent years to examine Taiwanese citizens’ sense of political efficacy. Previous literature assumes that the causal direction runs from efficacy to participation. No research has been conducted analyzing how political participation affects Taiwanese citizens’ sense of political efficacy. Neither is there any inquiry examining the impact of electoral outcomes on efficacy. Employing survey data collected by Taiwan’s Election and Democratization Study (TEDS) Project of 2004, this study treats political efficacy as the dependent variable and assesses the effects of voting and campaign activity. The empirical findings indicate that voter turnout per se does not contribute to the island citizens’ efficacious attitudes. It is the act of voting and campaigning for winning candidates that are associated with increased external political efficacy, which suggests that election effects are a product of both participation and outcomes. Electoral participation, however, does not affect an individual’s sense of internal political efficacy at all.