This book delves into the critical role of eco-labels as signals in a marketplace increasingly driven by consumer demand for sustainable products. It begins with an exploration of how eco-labels function within a tripartite system involving consumers, producers, and third-party certifiers, highlighting the challenges and opportunities in their creation, promotion, and validation. Building on this foundation, the book examines the influence of visual aesthetics on consumer perceptions, drawing from aesthetic psychology and marketing literature to explore how design elements—such as visual and conceptual complexity, color, and text—affect consumer attitudes and trust. The empirical core of the book evaluates real-world eco-labels, analyzing how their visual design impacts sustainability perceptions and label adoption. By synthesizing theoretical insights and empirical findings, the book offers practical recommendations for marketers, designers, and policymakers, aiming to improve eco-label effectiveness in fostering sustainable consumer behavior.