Abstract: This study investigated the proposition that self–perceived knowledge or self-expertise is a primary theoretical construct in understanding third–person perception of television violence effects in a sample of Americans (mean age 43 yrs old). Consistent with most past research, the findings confirm people’s third–person tendencies to attribute greater media effects of television violence on other people than on themselves. As hypothesized, self–perceived knowledge was a stronger predictor of third–person perception than sociodemographic variables (demographics, ideology, and media use). The study also found that self–perceived knowledge was more likely to moderate than mediate the relationship between sociodemographic variables and third–person perception. Whereas a moderator affects the strength of the relationship between an independent variable and a dependent variable, a mediator explains the relationship between the two variables. In sum, the findings indicate that respondents’ judgments of their superior self–perceived knowledge of television violence might be of theoretical significance in third–person effect research. (PsycINFO Database Record (c) 2004 APA, all rights reserved)