Greenwashing has emerged as a critical challenge in sustainable marketing, with significant implications for consumer perceptions, brand outcomes, and organizational development. This study examines the mediating role of consumer skepticism in the relationship between greenwashing practices, consumer trust, and brand equity, with particular attention to sustainability planning and long-term brand development. Using data collected from 572 respondents, the study employs Partial Least Squares Structural Equation Modeling (PLS-SEM) to test the proposed conceptual framework. The results indicate that greenwashing practices significantly increase consumer skepticism and exert a direct negative effect on consumer trust, thereby undermining sustainability-driven development strategies. Consumer skepticism is also found to have a significant negative impact on both consumer trust and brand equity, highlighting its central role in shaping consumer evaluations of environmental claims and long-term brand development. In contrast, consumer trust demonstrates a strong positive influence on brand equity, emphasizing its importance as a foundational element of sustainable brand development and competitive positioning. Mediation analysis confirms that consumer skepticism significantly mediates the relationships between greenwashing practices and consumer trust, as well as between greenwashing practices and brand equity, underscoring its role as a critical psychological mechanism through which greenwashing disrupts organizational development outcomes. The findings contribute to the literature by empirically validating consumer skepticism as a key pathway linking unethical sustainability communication to weakened trust and brand equity.