BACKGROUND/OBJECTIVES: Socioeconomic inequalities in diet quality are consistently reported, but few studies have investigated whether and how such inequalities vary across ethnic groups. This study aimed to examine differences in diet quality and socioeconomic patterning of diet quality across ethnic groups. SUBJECTS/METHODS: Cross-sectional data from the HELIUS study were used. Dutch, South-Asian Surinamese, African Surinamese, Ghanaian, Turkish and Moroccan adults (aged 18-70 years) were randomly sampled, stratified by ethnicity. Dietary intake was estimated among a subsample (n = 4602) from 200-item, ethnic-specific food frequency questionnaires, and diet quality was assessed using the Dutch Healthy Diet Index 2015 (DHD15-Index). Wald tests were used to compare non-Dutch and Dutch participants. Adjusted linear regression models were used to examine differences in DHD15-Index by three indicators of socioeconomic position: educational level, occupational status and perceived financial difficulties. All analyses were stratified by sex. RESULTS: Dutch participants had lower median DHD15-Index than most ethnic minority participants (P < 0.001). Lower educational level was associated with lower DHD15-Index among Dutch men (Ptrend < 0.0001), South-Asian Surinamese men (Ptrend = 0.01), Dutch women (Ptrend = 0.0001), African Surinamese women (Ptrend = 0.002) and Moroccan women (Ptrend = 0.04). Lower occupational status was associated with lower DHD15-Index in Dutch men, β -7.8 (95% CI -11.7, -3.9) and all women (β -4.4 to -8.8), except Turkish women. DHD15-Index was not associated with perceived financial difficulties in most groups. CONCLUSIONS: We observed variations in diet quality across ethnic groups. Low socioeconomic position was not consistently associated with poor diet quality in all ethnic groups. This may be due to ethnicity-specific retention of traditional diets, irrespective of socioeconomic position.