Given that consumers value quality, and advertising content informs consumers’ beliefs about quality, it is not surprising that high-quality brands emphasize quality in their advertising content. What is less obvious is whether firms with lower-quality brands should also follow suit and emphasize quality in their advertising to signal a higher quality. We examine this issue and study the effectiveness of quality-based advertising messages. Our field study relates brands’ monthly sales to their advertised quality claims across 1,876 print ads in national magazines and Consumer Reports–based product quality ratings over more than two decades. Contrary to the generally held yet erroneous belief in the efficacy of low-quality products emphasizing quality in their advertising, we demonstrate that (1) it is not beneficial for a low-quality firm to emphasize quality in its advertising, and (2) it is effective for a high-quality firm to do so. An analysis of parameter values from a published category-agnostic simulation and an experiment that examines consumers’ responses to quality claims in a second product category yields convergent insights.