This paper presents the procedures and findings of a systematic review of research on the impact of testing on students' motivation for learning. The review was undertaken to provide evidence in relation to claims that, on the one hand, testing raises standards and, on the other, that testing, particularly in high stakes contexts, has a negative impact on motivation for learning that militates against preparation for lifelong learning. Motivation is considered as a complex concept, closely aligned with 'the will to learn', and encompassing self-esteem, self-efficacy, effort, self-regulation, locus of control and goal orientation. The paper describes the systematic methodology of the review and sets out the evidence base for the findings, which serve to substantiate the concern about the impact of summative assessment on motivation for learning. Implications for policy and practice are drawn from the findings.