This study examines how Japanese consumers’ awareness of multiple eco-labels, specifically Organic JAS and RSPO, affects their willingness to pay more for eco-labeled cosmetic products. Drawing on the Theory of Planned Behavior (TPB) and Signaling Theory, this study models the interaction between awareness of these two eco-labels and their influence on organic cosmetic buying intentions. Using statistical analysis of survey data from 505 Japanese consumers, the findings reveal that heightened awareness of the Organic JAS label significantly increases the willingness to pay more for eco-labeled cosmetics. However, when awareness of the RSPO label is also present, the positive effect of Organic JAS awareness diminishes, indicating that multiple eco-label signals may interfere with each other. These results underscore the complexity of consumer perceptions regarding eco-labels and suggest that the effectiveness of eco-labels as green marketing tools depends not only on raising awareness but also on understanding how different labels interact to influence consumers’ willingness to pay in the Japanese cosmetics market.