The Institute for Governance and Sustainable Development (IGSD) is a Washington D.C.-based left-of-center environmentalist organization. It works to strengthen environmental law and expand environmental governance institutions.
IGSD supports the Green New Deal and other radical environmentalist programs that would eliminate the use of conventional fuels. The organization also works with international organizations to promote agreements to combat climate change. The Institute has also engaged in lawsuits against energy companies to force them to pay for alleged damages to the environment. The organization is one of the largest U.S. government grant recipients among environmentalist organizations that supported the Green New Deal proposal. 
IGSD targets professionals to push its environmentalist agenda, working with lawyers, political scientists, economists, and scientists.  Within the United States, the Institute has established the Program on Governance for Sustainable Development at the University of California-Santa Barbara to provide a research basis for environmentalist projects. IGSD has also collaborated with American University’s Washington College of Law on various projects and taught at American universities including Duke and Johns Hopkins. 
IGSD also has a substantial international footprint, working with international organizations including the United Nations to encourage countries to sign various treaties to combat climate change.  Within the United Nations, the Institute works as counsel to the United Nations Environment Programme’s Economics and Trade Branch on issues of international law and economics. IGSD also works pro bono with some developing countries to advise them on trade negotiations and offers pro bono and reduced-cost representation to environmentalist organizations. 
IGSD is a prominent supporter of the Green New Deal. The proposal would set a hard cutoff date to completely phase conventional fuels out of the economy and would place new restrictions on industries ranging from agriculture to transportation. The Green New Deal would also expand the role of government in nearly every aspect of American life in pursuit of environmentalist policies. 
In August of 2017, the IGSD established the Center for Climate Integrity (CCI). CCI supports lawsuits against energy companies to push for environmental regulation. CCI works to encourage citizen groups and governments to sue energy companies, billing the lawsuits as necessary to force polluters to pay for the damage of climate change instead of shifting the costs to taxpayers.
IGSD frequently seeks to expand top-down environmental regulations, claiming that current climate change policies, such as the Paris Climate Accords, are inadequate due to the opposition of fossil fuel companies.  IGSD is also working to expand the Montreal Protocol to include more types of gases and chemicals as subjects for regulation. The Montreal Protocol originally phased out most ozone-depleting substances, but IGSD supports expanding the treaty to include phasing out the production and use of hydrofluorocarbons, which are used in air conditioning among other appliances. 
In 2018, IGSD raised $9.9 million in revenue and spent $8.8 million.  IGSD has received over $6.2 million in grants from the U.S. government since 2008. The grants have come mostly from the Environmental Protection Agency (EPA) and the Department of Commerce.