Enthusiasm for deliberative democracy has grown in recent years, as many believe that it can create better citizens generally, and particularly increase their perceptions of political efficacy. Although the “efficacy effect” is frequently touted as a rationale for engaging in deliberative processes, there is little empirical research on the subject. This study examines the impact on perceptions of internal and external political efficacy of participation in one manifestation of a deliberative democracy process, the AmericaSpeaks 21st Century Town Meeting. Using quasi-experimental, longitudinal survey data, the study finds partial support for the claim that deliberative democracy produces the efficacy effect. Implications of the findings and directions for future research are discussed.