Political efficacy is addressed within the framework of social cognitive theory and a new measure to assess perceived political self-efficacy is presented. Three studies document the validity of the new scale of measurement. The first study (N = 1673) examined the psychometric properties of the scale in accordance with classical test theory. This led to the identification of a unidimensional factor structure, including perceived political self-efficacy in promoting one's own political opinion, in sustaining the political programs of the party to which one belongs, and in monitoring one's own political representatives' commitment. The second study (N = 632) further confirmed the internal and construct validity of the scale; criterion validity was also investigated using several indicators of political interest and participation. The third study (N = 1176) showed that politicians holding offices have higher levels of perceived political self-efficacy than partisans and voters, further corroborating the criterion validity of the scale. Copyright © 2009 John Wiley & Sons, Ltd.