Amidst increased research on mergers in higher education, studies addressing micro level processes are scarce and fragmented across disciplines: our aim is to systematically review existing studies, providing implications for research and practice. We grouped 21 studies from different countries under four themes: academic identity and self-image; cultural integration; staff reaction; teaching and research. Timing, status of institutions and staff, and disciplinary cultures apparently affect post-merger micro-level processes. Policy reforms might indirectly address micro-level processes following a merger, for example in a change of academic identities. Few studies investigated the impact of mergers on teaching and research activities. Studying merger consequences for academic core activities is complex, requiring a longer perspective involving students, staff and quantitative indicators. Longitudinal design in further studies might investigate changes from different angles and for different staff groups and students, exploring country differences in micro-level processes, applying a comparative design. Despite limitations, our review might inform the planning of merger processes regarding reactions at micro level.