In this study, we compared how sustainability, children's agency, and play are addressed in preschool curricula in Sweden and Turkey. Content analysis was used to analyse, interpret, and compare the content. The findings indicated that sustainability is explicitly integrated into the Swedish curriculum but only partly mentioned in the Turkish curriculum. Play is a core part of children's learning in Sweden, whereas, in Turkey, play is mainly referred to as a method. The Swedish preschool curriculum emphasises democracy as a central aspect, which reflects the dedication to fostering children's agency and their comprehension of rights and participation. The Turkish curriculum, meanwhile -- while acknowledging democratic principles, child rights, and participation -- does not provide a comprehensive framework for promoting children's agency. Our qualitative study contributes to knowledge about policies that may lead to practices concerning preschool education in Sweden and Turkey that focus on sustainability, children's agency, and play.