<![CDATA[Abstract: Changes in consumption patterns—which are increasingly oriented toward the fulfillment of desires and the accumulation of material goods—present economic, social, and ecological challenges. Excessive consumption can lead to the wasteful use of resources, an increase in waste, and a weakening of social responsibility in economic activities. This study aims to analyze the concept of simplicity in Gus Dur’s thought, understand simplicity as an ethic of economic behavior, and examine its relevance in fostering sustainable economic behavior. The study employs a qualitative approach using library research. Data were obtained from Gus Dur’s works as primary sources, as well as books, scientific journal articles, institutional reports, and previous studies as secondary sources. Data collection was conducted through documentary analysis, while the analysis employed interpretive content analysis involving the stages of data reduction, categorization, interpretation, comparison, and synthesis. The research findings indicate that simplicity in Gus Dur’s philosophy is not merely a frugal lifestyle or a restriction on possessions, but rather a moral value that emphasizes propriety, self-control, a rejection of materialism, and a focus on utility. In economic behavior, this value can serve as a guideline for distinguishing between needs and wants, controlling consumption, and considering the social and ecological impacts of economic decisions. Simplicity is relevant as an ethic of sustainable economics because it promotes consumption that is sufficient, appropriate, beneficial, and environmentally responsible. Consequently, Gus Dur’s philosophy can be developed as an ethical framework for fostering economic behavior that is oriented not only toward material well-being but also toward the sustainability of life.]]>
