The role of socio-economic status (SES) on the misreporting of food and energy intakes is not well understood with disagreement in the literature. The aim of this study was to examine the associations between low energy reporting, dietary quality and SES in a representative sample of adults. Dietary data were collected using 2 d of 24-h recalls for 6114 adults aged 19 years and over, participating in the Australian National Nutrition and Physical Activity Survey 2011–2012. Low energy reporters (LER) and plausible reporters (PR) were identified. Discretionary food intake was used as a proxy indicator of diet quality. SES was determined using area-level SES and educational attainment. Regression analysis was applied to examine the effects of LER and SES on diet quality, adjusting for potential confounders. LER was more common in populations of lower SES than higher SES (area-level OR 1·46 (95 % CI 1·06, 2·00); education OR 1·64 (95 % CI 1·28, 2·09). LER and SES were independently associated with diet quality, with LER reporting lower percentage energy from discretionary foods compared with PR (27·4 v. 34·2, P < 0·001), and those of lower area-level SES and education reporting lower diet quality compared with those of higher SES (33·7 v. 31·2, P < 0·001; and 33·5 v. 29·6, P < 0·001, respectively). No interaction effect was found between LER and SES, indicating percentage energy in discretionary foods was not differentially misreported across the SES areas (0·3078) or education (P = 0·7078). In conclusion, LER and higher SES were associated with better diet quality.