Research on policy integration has become an important part of public policy scholarship by analyzing how policymakers create linkages between policy subsystems to deal with complex policy problems. To develop this research program further, it is crucial to know how policy integration relates to broader theoretical and methodological developments in the field of public policy studies. This article reviews the empirical literature on policy integration in the last 10 years focusing on concepts, theories, research design, and methods, drawing upon a sample of 413 articles. Results show no systematic patterns in how these four dimensions combine in policy integration research. Above all, stages and theories of the policy process appear to be incorporated in policy integration studies only to a very limited extent. These findings point to four new directions for policy integration research: (1) Striking a balance between conceptual richness and consolidation regarding "policy integration"; (2) An increased focus on the evaluation of integrated policies; (3) More attention to actor-oriented and explanatory theories; (4) The potential for combining qualitative and quantitative methods of data analysis.