There is growing consensus among researchers, educators, and policy makers about the need for greater emphasis on ambitious student-centered mathematics instruction in light of mounting concern about student mathematics performance in the intermediate grades and beyond. To facilitate educators’ adoption of ambitious mathematics instructional practices, recent reform initiatives, such as the Common Core Standards for Mathematics (CCSM), have specified the content elementary students should learn and the practices in which students should engage, while organizations such as the National Council of Teachers of Mathematics (NCTM) have assumed responsibility for making recommendations for improving instructional practices in mathematics. In particular, since 1989, the NCTM has continually called for the increased use of manipulative materials at all levels of mathematics education in order to support students’conceptual and procedural understanding. However, the evidence for the effects of using manipulatives to support student mathematics achievement across the primary and secondary grades is generally mixed. Investigating reasons for such contradictory findings through rigorous inquiry is important for advancing both theory and practice in mathematics education.The present systematic review and meta-analysis seeks to address this issue in order to strengthen communication and research partnerships with educators, administrators, and policy makers interested in effective practices in mathematics education.