We live in a critical time where a variety of global difficulties and problems of an ecological, social, and economic nature generate new questions about the future of humanity. In the Swedish curriculum for the preschool, sustainable development is stated as an important part of the preschool’s core values and mission, which is followed up with goals. Therefore, there is a need to clarify and anchor education for sustainable development in preschool education. This article presents a study in which 153 Swedish preschool teachers describe their most important motives for teaching about sustainable development in their preschools. The study has a qualitative approach and is carried out within the framework of a critical theoretical perspective that examines cultural conceptions and understandings of social reality in a specific institutional socio-historical context. In the preschool teachers’ descriptions, a wide range of motives appears regarding why it is important to teach about sustainable development in preschool: To counteract unsustainable lifestyles, To follow the governing documents, To take responsibility for a sustainable present and future, and To equip children for the future. The study also shows that teaching for sustainability includes developing knowledge, creativity, problem-solving skills, critical thinking, action skills, innovative thinking, and change. Children’s participation for a sustainable present and future is presented as decisive for this change.