The purpose of this study is to learn how early childhood educators make ethical decisions. The study also explores how these educators might learn to base their ethical decisions on a professionally accepted ethical code through a participatory professional development process. The professional code of ethics used in this study is the National Association for the Education of Young Children (NAEYC) Code of Ethical Conduct. Study participants are six early childhood teachers who work with children aged Birth through 5 years old in a University Lab School. The results of the analysis show that from pre-assessment to the post-assessment, teachers shifted in how they identified and resolved professional ethical dilemmas. As a result of participation in the professional learning and discussions of ethical dilemmas, participants gained new understanding and familiarity with professional ethical behavior and were able to distinguish ethical dilemmas from other judgments as they grew more familiar with and able to use the NAEYC Code. Although participants demonstrated that they are better able to identify and resolve ethical dilemmas, this study concludes by suggesting additional professional learning and research on how protocols and professional learning communities can support teachers' ethical reasoning. (author abstract)