In this introduction to the special issue of Sustainability on environmental laws and sustainability, we attempt to synthesize key lessons from the issue’s ten substantive articles. These lessons involve the use of law to achieve integrated decision-making, the use of pre-existing laws to foster sustainability, the centrality of sub-national governments in achieving sustainability, the background law of unsustainable development, the growing importance of climate change, the need to use law to protect and restore ecological integrity, the importance of judicial review and nongovernmental organizations, the need to translate sustainability into specific legal principles, the challenge of creating an appropriate national legal structure for sustainability, the importance of sustainability assessment tools and institutions before and after laws are adopted, and the importance of “soft” law.