<p>Governments across Europe have implemented mergers between higher education institutions (HEIs) to reduce costs and to increase HEIs’ performance. However, few studies have empirically confirmed the efficiency of such mergers for faculty publication performance. This study addresses this gap by analysing a major reform in the Norwegian higher education system, where institutions were merged with goals such as fostering high-quality research, creating robust academic communities, and developing world-leading academic environments. We specifically analyse the pre- and post-merger publication performance of academics, using a high-quality bibliometric database with longitudinal data and survey results on job characteristics, organizational change, leadership, and commitment. We compare the performance of academics across different types of mergers: mergers between university colleges, mergers of university colleges with universities, and non-merged institutions. The study shows that improvements in research performance have only been partially realized. The mergers did not benefit the performance of existing staff; however, merged institutions appear to have attracted new personnel with stronger research qualifications and higher research output.</p>