Although social–emotional learning (SEL) and ethics education are important, it remains a challenging issue to effectively implement these practices. In this study, a Philosophical Ethics in Early Childhood approach is proposed for developing children’s social–emotional competence and Theory of Mind. To evaluate the effectiveness of this expanded intervention, an experiment was conducted by assigning 73 children aged 3–5 to an experimental group (N=37) and a comparative group (N=36). Parents and teachers completed Head Start Competence Scales, the Theory of Mind Inventory and parent and teacher questionnaires. Teacher and Child Interviews were conducted. According to the teachers’ reports, the experimental group children demonstrated significantly increased social–emotional competence skills and increased understanding of their own and others’ emotions compared to the comparative group children. (author abstract)