The article explores the use of high-stakes testing and its effect on content, knowledge form and pedagogy. A qualitative metasynthesis of 49 qualitative studies indicated that the primary effect of high-stakes testing is that curricular content is narrowed to tested subjects, subject knowledge is fragmented and teachers increase the use of teacher-centered pedagogies. However, in a significant minority of cases the tests led to expanded curricular content, integration of knowledge and more student-centered pedagogies.