For today, it is known that Earth is the only planet, where mankind can live. Human beings have an important impact on Earth through consumption of resources and increasing population. Just 10 years ago, few people were worried about the situation of the Earth. Only few people were dealing with gobal warming, ozone layer depletion, increasing population and loss of biodiversity. But today, environmental problems and environmental degradation is everybody's concern (Vogel, 2007). To provide the continuity of life, human beings should be aware of their impacts on the environment. To decrease the environmental degradation, educating environmentally literate citizens is important. Thus, education provided in schools has an important role in raising environmentally literate generations.

As places of learning, schools are the physical settings for the educational process and children spend a considerable amount of time in schools. The importance of the contribution of schools to achieving environmentally literate citizens cannot be overestimated. In order to provide necessary understanding for the public needed for the solution of environmental problems, environmental education should be integrated into the whole formal school system (UNESCO, 1977). According to Orr (1992) in schools students should learn that they are a part of, not apart from, natural systems. Orr believes strongly in importance of environmental literacy and he states that "no students should graduate from any educational institution without a basic comprehension of the outlined criteria that makes one ecoliterate" (Orr, 1991, n.p.)

Today, most of the educators would agree that something should be done in schools to educate environmentally literate students. However, there are a few school examples that help students better understand how sustainable development can be achieved. With this respect, an international award program, named as eco-school, emerged to accomplish sustainable development in schools. Eco-school program was developed by Foundation of Environmental Education as a means of delivering Agenda 21 commitments (http://www.fee-international.org). The major aim of this program is to prepare children for sustainable living and to show that sustainable living is about finding solutions to the problems we confront and improving the people's quality of life without destroying the environment. By the rise of the eco-school program, it gained an increased attention throughout the world and today 27,000 schools from 44 countries including Turket are enrolled to the program. Eco-schools program is administered in Turkey by Turkish Foundation for Environmental Education since 1995. Hundreds of schools; kindergartens, primary, elementary and secondary schools; enrolled to the project all over the country. Although the program is implemented in such a wide area, there are not enough research studies questioning the effectiveness of eco-schools on students' environmental literacy. With this respect, this study questions the effectiveness of eco-school application to educate environmentally literate children. For this purpose, this study is dealing mainly with the effects of eco-schools on 7th grade students environmental literacy levels.

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