Sustainable entrepreneurship has emerged as a pivotal solution to address environmental, social, and economic crises. However, developing sustainable ventures, particularly in the early stages, faces significant branding challenges. This chapter examines four core challenges: competition with established brands (due to resource disparities in finance and human capital), building trust (amid greenwashing risks and information asymmetry), shifting consumer mindsets (where cost and convenience often overshadow sustainability priorities), and low customer awareness of sustainability concepts. Sustainable branding not only serves as a tool to attract investors and customers but also reduces information gaps and enhances trust, driving the growth of sustainable markets. The case study of “Zeero,” an Iranian smart transportation startup, illustrates practical challenges such as competing with dominant ride-hailing platforms (e.g., Snapp and Tapsi), addressing public unawareness of eco-friendly alternatives, and emphasizing data transparency to validate environmental impact. By integrating authenticity, transparency, and strategic stakeholder engagement, sustainable entrepreneurs can overcome resource constraints, differentiate themselves in competitive markets, and achieve long-term viability. The chapter emphasizes the importance of integrating sustainability into core branding strategies to navigate complexities and promote systemic change toward responsible business practices.