News diversity is increasingly gaining momentum and relevance in academic research, but quantifying and qualifying the term remains problematic. This paper presents the results of a structured meta-synthesis literature review, in which all relevant publications dealing explicitly with news diversity, media diversity or content diversity of the 21st century found on Scopus (n = 61) are coded and analysed. Findings reveal that studies dealing with these concepts are on the rise in absolute numbers, but also that their theoretical foundations predominantly still lie in the 1990s. From the viewpoint that said foundations have become inadequate to study and understand news diversity in the digital era, we propose an integrated conceptual framework, model and definition to operationalise news diversity, which takes into consideration recent changes in journalism as media concentration dynamics and changing patterns in news production and consumption. It does so by developing a typology of five categories of diversity (ownership, brand, production, content, consumption) and presenting three levels from which news diversity can be studied (the macro level of the media market, the meso level of the media company and the micro level of the media brand). Ultimately, the paper proposes the adoption of mixed methods research to reveal more about the characteristics, contexts and constraints within any media market.