Increasingly, the characteristic that distinguishes a professional nurse is cognitive rather than psychomotor ability. Critical thinking is an essential component of nursing. Yet, no clear definition or conceptualization of critical thinking for nursing judgment has existed. Lack of consensus and overlapping definitions may well diminish the profession's ability to articulate this concept and facilitate its development. This article proposes the Critical Thinking Model for Nursing Judgment, which specifies five components: specific knowledge base, experience, competencies, attitudes, and standards. The model has three levels of critical thinking: basic, complex, and commitment. It provides a definition and conceptualization of critical thinking based on a review of the literature and input from nurses and nurse educators. The model provides a first step for development of further research and educational strategies to promote critical thinking as an essential part of autonomous, excellent nursing practice.