Greenwash (derived from whitewash) is a term that environmentalists and other critics give to the activity of giving a positive public image to putatively environmentally unsound practices. The term arose in the aftermath of the Earth Summit held in Rio de Janeiro in June 1992. Corporate lobby groupss saw the Earth Summit as a prominent platform from which to redefine their role and to shape the emerging debate on environment and sustainable development.

Critics claim that the business community emerged from the Earth Summit with no binding rules or regulations to hinder environmentally or socially damaging activities. They claim further, that these business interests convinced governments and international organizations to allow them to operate increasingly unregulated in the global market.

Corporations continue to claim that the promotion of free markets policies, new technology and economic growth are essential to promoting sustainable development, and increasingly claim that they are more environmentally aware. Critics, however, claim that there is little evidence transnational corporations are substantially changing their behavior despite their rhetoric; and they claim that many corporations remain the primary creators of environmentally damaging and unsustainable technologies.