Early childhood education aims to support children to develop cognitive, social, and motor skills, alongside values and ethics central to sustainability. From a Nordic perspective, this chapter reflects on how global citizenship education in preschool can illuminate possibilities and barriers to developing a whole school approach to sustainability. A review of Nordic policy and research identified four perspectives rooted in the global citizenship tradition that can support a whole school approach to sustainability: The greening of the whole preschool; The whole child’s learning; Wholeness in preschool teaching; and Thematic approach as a perspective on a whole preschool. We propose that efforts to implement a whole school approach to sustainability could be aligned with these perspectives. Nonetheless, Nordic preschools currently lack robust engagement with society—a perspective that requires further cultivation. To advance, empirical studies are needed to explore how a whole school approach to sustainability can be developed and implemented within preschool education.