Diet quality has been linked to socio-economic status. However, evidence within rural and regional populations is lacking. This cross-sectional study examined the relationship between diet quality and socio-economic position in adults living in rural and regional areas of Australia. The Australian Recommended Food Score (ARFS; range 0–73) measured diet quality (total and subscale scores). Area-level socio-economic position was determined by postcode-linked socio-economic index for areas (SEIFA), Index of Relative Social Advantage and Disadvantage scores, stratified into quintiles. The mean total ARFS (34·7; sd = 9·1; n 836) was classified as ‘getting there’. Findings showed significantly lower mean total ARFS between SEIFA quintile 1 (1 = lowest; mean total ARFS = 30·4; sd = 10·2; categorised as ‘needs work’) compared with all other SEIFA quintiles (F (44 831) = 8·44, P ≤ 0·001). Linear regression, adjusting for age, sex, income, education, employment status and household composition demonstrated significantly lower overall diet quality for SEIFA quintile 1 compared with SEIFA quintile 3 (B = –3·9; 95 % CI (–6·2, −1·5); P < 0·001) and lower subscale scores for vegetables (B = –1·6; 95 % CI (–2·7, −0·6); P = 0·003), fruit (B = –0·9; 95 % CI (–1·6, −0·1); P = 0·018) and grains (B = –0·6; 95 % CI (–1·3, −0·0); P = 0·050). After adjusting for individual confounders of diet quality, results indicate that lower area-level socio-economic position remained associated with poorer diet quality in this sample of rural and regional Australian adults. This suggests that broader social and environmental factors unique to these areas may impact diet quality and amplify individual barriers to achieving a healthy diet.