This article reports the findings of a survey of 558 teachers in England. It describes how conceptual and empirical insights from the literature informed the construction of questionnaire items to provide answers to questions about the way in which teachers value different classroom assessment practices and how congruent with these values they perceive their practices to be. Results from item, factor and cluster analyses reveal three underlying dimensions of assessment practice, sizeable values-practice gaps on two dimensions that appear to be in tension (promoting learning autonomy and performance orientation), and differences among teachers which show that over half of this sample report that they are unable to sustain practices across all dimensions in line with their values. We conclude that teachers are demonstrably committed to the values (not just the methods) of assessment "for" learning within a moral framework that gives importance to the quality of students' learning, yet they experience and need to resolve contradictions in order to realize their values. (Contains 7 figures, 5 tables, and 8 notes.)