Health inequalities represent a major societal threat and research has established that as long as we have social inequalities, we will have health inequalities. The Nordic countries currently lead the world in creating more equal societies. They have done so across multiple axes of inequalities, especially class- and gender-based inequalities. Despite this, research consistently finds persistent health inequalities in the Nordic countries and what is perhaps more puzzling is that these inequalities are sometimes larger than in countries with higher levels of inequality. In response, the Nordic Arena for Public Health Issues initiated a collection of indicators for health inequalities in 2017, and after reviewing 170 possible indicators, selected seven: life expectancy, self-assessed health, vegetable consumption, smoking, risk of social exclusion, physical activity among 15-year-olds, and a summary measure of income inequality. The goal is that all Nordic countries collect these indicators regularly and over-time, to enable monitoring and comparison of inequalities. To start with a good understanding of what each indicator means, this report provides a scientific overview of each. This includes discussions of why each indicator matters, and provides insights into what we know about the indicator within and outside of the Nordic countries. While the selection of the indicators represents an important first step in understanding health inequalities across the Nordic countries, they can only serve as the beginning. It is important to consider both other indicators and other sources of inequalities, for example based on immigration status. Similarly, the Nordic countries like the rest of the world face multiple challenges that are likely to increase societal inequalities. This report highlights global climate change and the COVID-19 pandemic as specific threats to our societies and consequently our health. While the exact consequences of these two ongoing, urgent crises are still unknown, one thing is certain: They will not affect all groups in society equally. The Nordic countries are in a leading position to reduce these consequences and promote social equality, but that requires careful policymaking grounded in scientific evidence on how social inequalities become health inequalities.