The purpose of this study is to describe ideas of preschool children about sustainable development. Basic qualitative research was utilized and 36 preschool children enrolled in four different preschools in Ankara were included in the study. Semi-structured interviews were used to obtain data related to ideas of preschool children on three pillars (Environmental, Economical, and Social Cultural) of Education for Sustainable Development and analyzed with inductive content analysis based on 7R's (reduce, reuse, respect, reflect, rethink, and redistribute). Participant children reflected their ideas about reduce, reuse, respect, and recycle; while they did not report any ideas related to reflect, rethink, and redistribute. Moreover, gender did not seem to have an influence on preschool children's ideas about sustainability. It is suggested that sustainable practices should be integrated into early childhood curriculum and supported by preschool teachers, parents and society.