PurposeThis study, a systematic review, focuses on the internationalisation of small and medium-sized enterprises (SMEs) originating in developing countries. It critically analyses, evaluates and synthesises studies featuring formal and informal institutions, embedded in social and business networks, as a marketing solution for institutional voids. The review shows that current international marketing studies downplay the role of informal institutions in the internationalisation of SMEs. Thus, the authors set a new research agenda for advancing the institutional theory to account for the impact of informal institutions and networks on firm internationalisation.Design/methodology/approachThis review followed five structured stages, including framing the research questions, identifying relevant studies, assessing their quality, summarising the evidence and interpreting the findings. Based on the systematic approach, 434 papers (374 from Web of Science, 60 from Scopus) were generated. Following that, the authors applied the qualitative inclusion/exclusion criteria, which yielded 63 papers. Their analysis involved three authors, with the fourth author focusing on ensuring quality in the analysis.FindingsThe study findings invite a different line of theorising market structures and processes focusing on the role of networks as an alternative to formal institutional systems. The outcome of our review suggests that there is scope for developing the institutional theory that account for the role of informal institutions and networks.Originality/valueBased on the analysis, we call for new theorisation, in the international marketing literature, which accounts for informal networking amongst internationalising SMEs in the light of institutional voids. Thus, the authors promote novel participatory, bottom to top understanding of relationship between institutions and enterprises.