Health partnerships are flourishing between institutions in the UK and low-and middle-income countries. Over the past five years, the Health Partnership Scheme (HPS), a UK government-funded programme managed by UK NGO THET, has supported health partnerships to undertake more than 200 projects in low-and middle-income countries [1]. All HPS-funded health partnerships, and most others, undertake monitoring and evaluation to generate high quality information and insights for effective management, stakeholder engagement, accountability and advocacy. There are many descriptive and reflective accounts of health partnerships in the literature (eg [2–5]) and a huge volume of grey literature in the form of project reports and evaluations. With greater interest and investment comes higher profile and closer scrutiny. While this can manifest as pressure to generate evidence of short-term, measurable achievements, rather than long-term, sustainable impact [6], some health partnerships have responded by rigorously strengthening their evaluation and research activities. Emerging questions about the mechanisms, efficiency and effectiveness of health partnerships have prompted a stream of published evaluations and research papers from clinicians [1], social scientists [7], health systems researchers, economists and others. These questions relate to two topics: what health partnerships are, and what health partnerships do.