BACKGROUND: Changing dietary patterns is essential to reducing the substantial environment impact of agriculture and food production systems. We performed a cross-country comparison of dietary patterns and their associated environmental impact in Europe, including by sociodemographic factors. METHODS: We analyzed pooled cross-sectional dietary records collected during 2010-18 from 10 European countries using the European Food Safety Authority (EFSA) Comprehensive European Food Database (16 508 adults; aged 18-79 years). Each food consumed was mapped to the corresponding environmental impact data using the SHARP Indicators Database, which provides greenhouse gas emission (GHGE) and land use (LU) values of approximately 900 foods. Total diet-associated environmental impact was calculated for each person and averaged across multiple days. Multivariable linear regression models were used to compare diet-associated GHGE and LU between population subgroups (gender, age, education and diet type) with country-level fixed effects. RESULTS: The mean dietary GHGE and LU per capita ranged from 4.0 kgCO2/day and 5.0 m2*year/day in Spain to 6.5 kgCO2eq/day and 8.2 m2*year/day in France. Diet-related GHGE and LU (per kg/food) were lower among females (2.6 kgCO2eq/day, B = -0.08, P < 0.01; 3.2 m2*year/day, B = -0.11, P < 0.01), older population aged 66-79 (2.6 kgCO2eq/day, B = -0.03, P < 0.01; 3.4 m2*year/day, B = -0.4, P < 0.01), people following vegetarian diets (1.7 kgCO2eq/day, B = -0.07, P < 0.01; 2.0 m2*year/day, B = -0.07, P < 0.01), and higher among individuals with secondary education (2.7 kgCO2eq/day, B = 0.05, P < 0.01; 3.6 m2*year/day, B = -0.05, P < 0.01). CONCLUSIONS: Environmental footprints vary substantially across countries, dietary patterns and between different sociodemographic groups in Europe. These findings are crucial for the development of country-specific food policies aimed at promoting environmentally sustainable diets.