Personalized learning programs are proliferating in schools across the United States, fueled by philanthropic dollars, tech industry lobbying, marketing by third-party vendors, and a policy environment that provides little guidance and few constraints. In this research brief, authors Faith Boninger, Alex Molnar, and Christopher M. Saldaña consider how we got to this point. Beginning with an examination of the history of personalized learning and the key assumptions made by its proponents, they review the research evidence and reflect on the roles and possible impacts of the digital technologies deployed by many programs. Despite many red flags, the pressure to adopt personalized learning continues to mount. The authors thus recommend that schools and policymakers pause in their efforts to promote and implement personalized learning until rigorous review, oversight, and enforcement mechanisms are established.