There is a growing body of cross-country comparisons in health systems and policy research. However, there is little consensus as to how to assess its quality. This is partly due to the fact that cross-country comparison constitutes a diverse inter-disciplinary field of study, with much variation in the motives for research, foci and levels of analyses, and methodological approaches.Inspired by the views of subject area experts and using the distinction between variable-based and case-based research, we briefly review the main different types of cross-country comparisons in health systems and policy research to identify pertinent quality issues.From this, we identify the following generic quality criteria for cross-country comparisons: (1) appropriate use of theory, (2) explicit selection of comparator countries, (3) rigour of the comparative design, (4) attention to the complexity of cross-national comparison, (5) rigour of the research methods, and (6) contribution to knowledge. This list may not be exclusive though publication and discussion of the list of criteria should help raise awareness in this field of what constitutes high quality research. In turn, this should be helpful for those planning, undertaking, or commissioning cross-country comparative research.