In response to rising environmental concerns, many corporations have adopted green branding strategies; however, not all such efforts are genuine. Greenwashing—the practice of misleading stakeholders about environmental practices—has emerged as a critical barrier to building public trust and promoting community engagement in sustainability. This study presents initial findings from a pilot survey conducted in Tamil Nadu, India, using a newly developed instrument to assess the impact of greenwashing on community engagement, with public trust as a mediating variable and environmental awareness as a moderator. A structured questionnaire with 77 items across four constructs—greenwashing, public trust, community engagement, and environmental awareness—was validated through expert review, exploratory factor analysis (KMO = 0.831), and reliability testing (Cronbach’s alpha > 0.87 for all constructs). Findings revealed a negative correlation between greenwashing and community engagement (r = –0.45), with public trust mediating this relationship. Moderation analysis confirmed that individuals with higher environmental awareness were less affected by greenwashing. Grounded in the Theory of Planned Behavior and ecological citizenship theory, the study highlights the deterrent effects of deceptive green claims on civic participation. Implications suggest the need for policy interventions, enhanced environmental education, and stricter regulations to counteract greenwashing and foster genuine community involvement.