Over the last four decades, Bangladesh has made considerable improvements in population health, this is in part due to the use of evidence to inform policymaking. This systematic review aims to better understand critical factors that have facilitated the diffusion of scientific evidence into multiple phases of health policymaking in Bangladesh. To do this an existing policy framework designed by Shiffman and Smith in 2007, was used to extract and synthesize data from selected policy analyses. This framework was used to ensure the content, context and actors involved with evidence-informed policymaking were considered in each case where research had helped shape a health policy. The ‘PRISMA Checklist’ was employed to design pre-specified eligibility criteria for the selection of information sources, search strategy, inclusion and exclusion criteria, and process of data extraction and synthesis. Through our systematic search conducted from February to May 2017, we initially identified 1859 articles; after removal of duplicates, followed by the screening of titles, abstracts and full-texts, 24 articles were included in the analysis. Health policy issues included the following topics: maternal and child health, tobacco control, reproductive health, infectious disease control and the impact and sustainability of knowledge translation platforms. Findings suggested that research evidence that could be used to meet key targets associated with the Millennium Development Goals (MDGs) were more likely to be considered as a political (and therefore policy) priority. Furthermore, avenues of engagement between research organizations and the government as well as collective action from civil-society organizations were important for the diffusion of evidence into policies. Through this article, it is apparent that the interface between evidence and policy formulation occurs when evidence is, disseminated by a cohesive policy-network with strong leadership and framed to deliver solutions for problems on both the domestic and global development agenda.