Green politics, or ecopolitics, is a political ideology that aims to foster an ecologically sustainable society often, but not always, rooted in environmentalism, nonviolence, social justice and grassroots democracy. It began taking shape in the Western world in the 1970s; since then, green parties have developed and established themselves in many countries around the globe and have achieved some electoral success.

The political term green was used initially in relation to die Grünen (German for "the Greens"), a green party formed in the late 1970s. The term political ecology is sometimes used in academic circles, but it has come to represent an interdisciplinary field of study as the academic discipline offers wide-ranging studies integrating ecological social sciences with political economy in topics such as degradation and marginalization, environmental conflict, conservation and control and environmental identities and social movements.

Supporters of green politics share many ideas with the conservation, environmental, feminist and peace movements. In addition to democracy and ecological issues, green politics is concerned with civil liberties, social justice, nonviolence, sometimes variants of localism and tends to support social progressivism. Green party platforms are largely considered left in the political spectrum. The green ideology has connections with various other ecocentric political ideologies, including ecofeminism, eco-socialism, degrowth and green anarchism, but to what extent these can be seen as forms of green politics is a matter of debate. As the left-wing green political philosophy developed, there also came into separate existence opposite movements on the right-wing that include ecological components such as eco-capitalism and green conservatism.

Adherents to green politics tend to consider it to be part of a higher worldview and not simply a political ideology. Green politics draws its ethical stance from a variety of sources, from the values of indigenous peoples, to the ethics of Mahatma Gandhi, Baruch Spinoza, and Jakob von Uexküll. These people influenced green thought in their advocacy of long-term seventh generation foresight, and on the personal responsibility of every individual to make moral choices.

Unease about adverse consequences of human actions on nature predates the modern concept of environmentalism. Social commentators as far apart as ancient Rome and China complained of air, water and noise pollution.

The philosophical roots of environmentalism can be traced back to enlightenment thinkers such as Rousseau in France, and later the author and naturalist Thoreau in America. Organised environmentalism began in late 19th-century Europe and the United States, as a reaction to the Industrial Revolution with its emphasis on unbridled economic expansion.

"Green politics" first began as conservation and preservation movements, such as the Sierra Club, founded in San Francisco in 1892.

Left-green platforms of the form that make up the green parties today draw terminology from the science of ecology, and policy from environmentalism, deep ecology, feminism, pacifism, anarchism, libertarian socialism, libertarian possibilism, social democracy, eco-socialism, and/or social ecology or green libertarianism. In the 1970s, as these movements grew in influence, green politics arose as a new philosophy which synthesized their goals. The Green Party political movement is not to be confused with the unrelated fact that in some far-right and fascist parties, nationalism has on occasion been tied into a sort of green politics which promotes environmentalism as a form of pride in the "motherland" according to a minority of authors.