For the last 30 years, encouraging employment has been the primary focus of U.S. anti-poverty policies. More recently, however, promoting the formation and maintenance of “healthy marriages” has emerged as a central feature of domestic social policy in the United States, with proposals pending that would allocate up to $1.5 billion to undertake and evaluate marriage promotion efforts. The central goal of this paper is to elaborate the implications of social science research for such efforts. We proceed as follows. After reviewing trends in family structure and theories and empirical evidence that attempt to account for these trends, we discuss various proposed marriage promotion policies and activities. Next, we identify potential challenges to designing, evaluating, and learning from these initiatives. We conclude with recommendations for research needed in order to move policy forward.