Background Health policy-making can benefit from more effective use of research. In many policy settings there is scope to increase capacity for using research individually and organisationally, but little is known about what strategies work best in which circumstances. This review addresses the question: What causal mechanisms can best explain the observed outcomes of interventions that aim to increase policy-makers’ capacity to use research in their work? Methods Articles were identified from three available reviews and two databases (PAIS and WoS; 1999–2016). Using a realist approach, articles were reviewed for information about contexts, outcomes (including process effects) and possible causal mechanisms. Strategy + Context + Mechanism = Outcomes (SCMO) configurations were developed, drawing on theory and findings from other studies to develop tentative hypotheses that might be applicable across a range of intervention sites. Results We found 22 studies that spanned 18 countries. There were two dominant design strategies (needs-based tailoring and multi-component design) and 18 intervention strategies targeting four domains of capacity, namely access to research, skills improvement, systems improvement and interaction. Many potential mechanisms were identified as well as some enduring contextual characteristics that all interventions should consider. The evidence was variable, but the SCMO analysis suggested that tailored interactive workshops supported by goal-focused mentoring, and genuine collaboration, seem particularly promising. Systems supports and platforms for cross-sector collaboration are likely to play crucial roles. Gaps in the literature are discussed. Conclusion This exploratory review tentatively posits causal mechanisms that might explain how intervention strategies work in different contexts to build capacity for using research in policy-making. Electronic supplementary material The online version of this article (10.1186/s12961-018-0277-1) contains supplementary material, which is available to authorized users.