This article presents an Environmental Identity Development model, which considers the progression of young children's self-cognitions in relation to the natural world. We recontextualize four of Erikson's psychosocial stages, in order to consider children's identity development in learning in, about, and for the environment. Beginning with "Trust in Nature vs. Mistrust in Nature," we argue that cognitions of comfort in the natural world vs. discomfort, provide the foundation for healthy environmental identity development. This trusting bond/relationship with nature allows children to gain "Spatial Autonomy" through collectively or independently creating their own sense of place in nature vs. feelings of doubt or "Environmental Shame." As children progress, they gain "Environmental Competencies," creative innovations to use the environment for both personal and social purposes vs. separation from nature or "Environmental Disdain." Such competencies promote children's agency in exercising "Environmental Action," applied care/ethics aimed at building a sustainable future, as opposed to behaviors that cause "Environmental Harm." Young children's environmental identity develops in diverse ways and in distinct sociocultural and geographical contexts. Caregivers/educators play a unique role in recognizing and supporting the needs of individual children as they progress towards healthy environmental identity development.