Effective food policies in Europe require insight into the environmental impact of consumers’ diet to contribute to global nutrition security in an environmentally sustainable way. The present study therefore aimed to assess the environmental impact associated with dietary intake across four European countries, and to explain sources of variations in environmental impact by energy intake, demographics and diet composition. Individual-level dietary intake data were obtained from nationally-representative dietary surveys, by using two non-consecutive days of a 24-h recall or a diet record, from Denmark (DK, n = 1710), Czech Republic (CZ, n = 1666), Italy (IT, n = 2184), and France (FR, n = 2246). Dietary intake data were linked to a newly developed pan-European environmental sustainability indicator database that contains greenhouse gas emissions (GHGE) and land use (LU) values for ∼900 foods. To explain the variation in environmental impact of diets, multilevel regression models with random intercept and random slopes were fitted according to two levels: adults (level 1, n = 7806) and country (level 2, n = 4). In the models, diet-related GHGE or LU was the dependent variable, and the parameter of interest, i.e. either total energy intake or demographics or food groups, the exploratory variables. A 200-kcal higher total energy intake was associated with a 9% and a 10% higher daily GHGE and LU. Expressed per 2000 kcal, mean GHGE ranged from 4.4 (CZ) to 6.3 kgCO2eq/2000 kcal (FR), and LU ranged from 5.7 (CZ) to 8.0 m2*year/2000 kcal (FR). Dietary choices explained most of the variation between countries. A 5 energy percent (50 g/2000 kcal) higher meat intake was associated with a 10% and a 14% higher GHGE and LU density, with ruminant meat being the main contributor to environmental footprints. In conclusion, intake of energy, total meat and the proportion of ruminant meat explained most of the variation in GHGE and LU of European diets. Contributions of food groups to environmental footprints however varied between countries, suggesting that cultural preferences play an important role in environmental footprints of consumers. In particular, Findings from the present study will be relevant for national-specific food policy measures towards a more environmentally-friendly diet.