Using the method of qualitative metasynthesis, this study analyzes 49 qualitative studies to interrogate how high-stakes testing affects curriculum, defined here as embodying content, knowledge form, and pedagogy. The findings from this study complicate the understanding of the relationship between high-stakes testing and classroom practice by identifying contradictory trends. The primary effect of high-stakes testing is that curricular content is narrowed to tested subjects, subject area knowledge is fragmented into test-related pieces, and teachers increase the use of teacher-centered pedagogies. However, this study also finds that, in a significant minority of cases, certain types of high-stakes tests have led to curricular content expansion, the integration of knowledge, and more student-centered, cooperative pedagogies. Thus the findings of the study suggest that the nature of high-stakes-test-induced curricular control is highly dependent on the structures of the tests themselves. (Contains 4 tables.)