Green startups play a crucial role in the transition to a sustainable economy, yet there is a gap in the literature about the legal and policy challenges these startups face. This Article seeks to fill that gap through interviews, surveys, and focus groups with senior law firm partners experienced in advising green startups, senior pro bono counsel and staff, chief executive officers of early-stage green startups, and senior staff at nonprofit legal aid groups. The Article identifies two major categories of challenges: substantive, including greenwashing, outdated regulatory frameworks, and insufficient understanding of social enterprise corporate forms; and legal service affordability challenges, including when and what pro bono and discounts to offer green startups. It recommends a comprehensive set of solutions, and argues that adopting them can help accelerate the transition to a sustainable economy to secure our future.