World Environment Day (WED) is a day that stimulates awareness of the environment and enhances political attention and public action. It is on 5 June. It was the day that United Nations Conference on the Human Environment began. The United Nations Conference on the Human Environment was from 5-16 June 1972. It was established by the United Nations General Assembly in 1972. The first World Environment Day was on 1973. World Environment Day is hosted every year by a different city with a different theme and is commemorated with an international exposition on the week that 5 June is on. World Environment Day is in summer in the Northern Hemisphere and winter in the Southern Hemisphere.

World Environment Day celebration in 2010 will be hosted in Rawanda City, Rawanda under theme "Many Species. One Planet. One Future".