The ethical rules for lawyers encourage zealous advocacy on behalf of clients, but do not incentivize lawyers to take steps that could minimize harm to the environment. This Article proposes a comprehensive set of amendments to the American Bar Association (“ABA”) Model Rules of Professional Conduct. The goal is to establish not only opportunities, but also obligations, for lawyers to promote environmental health. Certain proposals in this Article represent only a small extension of the present rules, and deserve consideration for immediate adoption, including a proposed liberalization of confidentiality rules to permit disclosures in the case of imminent environmental harm, an expansion of lawyers’ counseling duties, a reconceptualization of third-party harm, an enlarged scope of supervisory responsibility, and a redefinition of pro bono service. The Article goes on to discuss, without necessarily advocating, some more radical ideas for reform. These include a stricter rule against positional conflicts, a more lenient standard for evaluating frivolity of environmental claims, a heightened obligation of candor with respect to environmental harm, and greater accountability for environmental damage caused by lawyers and firms. The Article concludes by addressing foreseeable objections to its proposals. One possible problem is that an expanded whistleblowing duty might alienate clients from their counsel, increasing the risk of environmental harm. The Article also considers the risk of bifurcating the bar into pro-environment and anti-environment factions. Such concerns necessitate caution, but they cannot justify the ABA Model Rules’ currently tepid approach to protection of the environment.