Introduction - Maternal mortality remains a key indicator of maternal health and the performance of maternal care systems, even in wealthy countries, where it has become rare. Comparisons between countries can highlight common patterns or unique characteristics, thereby revealing causal mechanisms and potential avenues for improvement. Routine mortality data do not allow for a reliable characterization of maternal deaths. Our objective was to compare maternal mortality among European countries with robust systems for studying this mortality. Methods - A descriptive comparative study was conducted using data from eight European countries with robust systems for identifying, documenting, and investigating maternal deaths (Denmark, Finland, France, Italy, the Netherlands, Norway, Slovakia, and the United Kingdom). Maternal mortality ratios (MMR), defined as the number of maternal deaths per 100,000 live births during a given period up to 42 days after the end of pregnancy, were calculated and then compared with those obtained from official mortality statistics. MMRs by age, by women’s geographic origin/ethnicity, and by cause of death were also calculated. Results - MMRs, up to 42 days after the end of pregnancy, varied by a factor of 4, ranging from 2.7 in Norway and 3.4 in Denmark to 9.6 in the United Kingdom and 10.9 in Slovakia per 100,000 live births. Official mortality statistics underestimated maternal mortality by 36% or more everywhere except in Denmark. Age-specific maternal mortality rates were higher for the youngest and oldest mothers (pooled relative risks (RR): 2.17, with a 95% confidence interval, 95% CI: [1.38–3.43] for women aged 20 years and older, 2.10 [1.54–2.86] for those aged 35–39, and 3.95 [3.01–5.19] for those aged 40 and older, compared with women aged 20–29). Except in Norway, MMRs were generally higher among women born abroad or from ethnic minority backgrounds, defined differently across countries. Cardiovascular diseases were a leading cause of mortality in all countries. Only two countries, France and the United Kingdom, have a reliable system for measuring maternal mortality up to one year after the end of pregnancy; in both of these countries, maternal suicide was the second leading cause of maternal mortality up to one year after the end of pregnancy, following cardiovascular diseases. Conclusion - Strengthened systems for studying maternal mortality, such as the Confidential National Survey on Maternal Mortality in France, are essential for collecting reliable data on maternal mortality. Among European countries with such systems, there are differences in the levels and causes of maternal mortality up to 42 days postpartum, unrelated to variations in how maternal mortality is measured. In-depth analyses of differences in the quality of care and the performance of health systems at the national level are needed to further reduce maternal mortality by learning from best practices and the experience of other countries. Cardiovascular diseases and women’s mental health during and after pregnancy must be considered priorities in all countries.