Abstract Several scholars and institutions have made attempts at defining and conceptualising news diversity, underlying its increasing relevance within and beyond academia. However, very few have operationalised it for a given media market, let alone in more than one simultaneously. In this paper, we critically assess existing theories and studies and present main shortcomings on the conceptual, methodological and empirical levels. We proceed by applying and testing two different frameworks and methods for assessing news diversity, co-developed by the authors separately from one another, to two different yet in many regards similar European media markets: those of Norway and Flanders (Belgium). In doing so, we seek to properly operationalise news diversity and expand the body of internationally comparative news-related research in times of fundamental change in the news industry, its production practices and markets. We highlight obstacles and best practices for future research.