Preterm birth (PTB) is the world's leading cause of death in children under 5 years. In 2013, over one million out of six million child deaths were due to complications of PTB. The rate of decline in child death overall has far outpaced the rate of decline attributable to PTB. Three key reasons for this slow progress in reducing PTB mortality are: (a) the underlying etiology and biological mechanisms remain unknown, presenting a challenge to discovering ways to prevent and treat the condition; (ii) while there are several evidence-based interventions that can reduce the risk of PTB and associated infant mortality, the coverage rates of these interventions in low- and middle-income countries remain very low; and (c) the gap between knowledge and action on PTB--the "know-do gap"--has been a major obstacle to progress in scaling up the use of existing evidence-based child health interventions, including those to prevent and treat PTB.In this review, we focus on the know-do gap in PTB as it applies to policymakers. The evidence-based approaches to narrowing this gap have become known as knowledge transfer and exchange (KTE). In our paper, we propose a research agenda for promoting KTE with policymakers, with an ambitious but realistic goal of reducing the global burden of PTB. We hope that our proposed research agenda stimulates further debate and discussion on research priorities to soon bend the curve of PTB mortality.