The perceptions of laypeople about media and their effects are an important subject of communication science. This work develops a communication science conception of naive media theories and places it in the context of existing research on Third-Person Perception. Through guided interviews, central lay perceptions about media are explored, and their relevance for predicting Third-Person Perception is examined in a quantitative-empirical study. This work thus provides communication researchers with both a starting point for further exploration of lay theories and an expansion of the existing research perspective on Third-Person Perception.