Collaborations between the academy and governments promise to improve the lives of people, the operations of government, and our understanding of human behavior and public policy. This review shows that the evidence-informed policy movement consists of two main threads: ( a) an effort to invent new policies using insights from the social and behavioral science consensus about human behavior and institutions and ( b) an effort to evaluate the success of governmental policies using transparent and high-integrity research designs such as randomized controlled trials. We argue that the problems of each approach may be solved or at least well addressed by teams that combine the two. We also suggest that governmental actors ought to want to learn about why a new policy works as much as they want to know that the policy works. We envision a future evidence-informed public policy practice that ( a) involves cross-sector collaborations using the latest theory plus deep contextual knowledge to design new policies, ( b) applies the latest insights in research design and statistical inference for causal questions, and ( c) is focused on assessing explanations as much as on discovering what works. The evidence-informed public policy movement is a way that new data, new questions, and new collaborators can help political scientists improve our theoretical understanding of politics and also help our policy partners to improve the practice of government itself.