Aims to address a gap in the literature about quality criteria for validity and reliability in qualitative research within the realism scientific paradigm. Six comprehensive and explicit criteria for judging realism research are developed, drawing on the three elements of a scientific paradigm of ontology, epistemology and methodology. The first two criteria concern ontology, that is, ontological appropriateness and contingent validity. The third criterion concerns epistemology: multiple perceptions of participants and of peer researchers. The final three criteria concern methodology: methodological trustworthiness, analytic generalisation and construct validity. Comparisons are made with criteria in other paradigms, particularly positivism and constructivism. An example of the use of the criteria is given. In conclusion, this paper's set of six criteria will facilitate the further adoption of the realism paradigm and its evaluation in marketing research about, for instance, networks and relationship marketing.