This study assesses the practices and environmental properties of preschools implementing the Eco-Schools program, targeting education for sustainable development (ESD) in terms of the program's environmental, sociocultural, and economic pillars. Qualitative and quantitative methods were used. The sample group, determined through criterion sampling, comprised four private and four public preschools in Ankara. A school observation form was used to examine the schools' environmental properties, and a teacher scale was devised to determine teachers' ESD practices. One-on-one interviews were conducted with 16 teachers. Private schools were found to have more elements within all three ESD pillars than public schools. A statistically significant relationship was found between the scores of teachers working at public versus private preschools and between their scores for the environmental and economic pillars. It is suggested that educators, children, and their families be informed about ESD practices and that Eco-Schools programs be made widespread in early childhood.