This essay aims at conceptual clarification within the field of curriculum. The concepts of curriculum theory, design, and practice are approached from the point of view of axiology. The argument presented is based on a distinction between value principles and value judgments and the type of justification involved in reasoning about such principles and judgments of value. It is asserted that nonnormative grounds may be found for justifying educational value principles although the principles have a normative function with regard to curricular practice. Further, the level of classroom practice is characterized as normative and involving the use of value judgments. Theorizing within the field of curriculum is thus defined as a nonnormative endeavor aimed at marking off a domain of educational value (to be distinguished from domains of moral, aesthetic, political, religious and other types of value). A curriculum theory is a set of value principles on this account, while a design is factual in nature and serves as a bridge between theory and practice. Curricular practice consists of judgments and actions based on judgments of educational value. Curricular practice is, therefore, normative. (Author)