Much of the current focus on the use of ultra-thin models in fashion magazines can be attributed to Madison Avenue which still operates under a “Thin Sells” ethos. Research to date, however, has provided equivocal evidence of the efficacy of thin models in advertising (Yu 2014). The present study’s two related objectives include: (1) determining whether model size has an impact on advertising effectiveness, and (2) if internalization of the thin ideal moderates this relationship. Study results suggest model size in fashion advertisements has no main effect on advertising effectiveness. Additionally, thin ideal internalization moderates the model size – advertising effectiveness relationship. Women who internalized the thin ideal were more receptive to thin models compared to average-size models. For low internalizers, model size has no significant impact on advertising effectiveness. These findings suggest that the current “thin sells” fixation is a gross oversimplification of how women respond to advertising. Directions for future research and study limitations are discussed.