Generally, young adults in Australia have poor diet quality, increasing their risk of chronic disease(1). Young adults use social media for nutrition-related information (SMNI), including recipes, product details and dietary advice(2,3). Such social media use may have implications for nutrition knowledge, confusion, and backlash towards nutrition science, which could impact dietary behaviours including diet quality and restrained eating. The purpose of this study was to examine young adults’ use of SMNI, and the association between nutrition-related social media use, diet quality and restrained eating and the role of potential mediators. A cross-sectional survey of young adults (aged 22–29) living in Australia was conducted (n = 200). The exposure variable, use of SMNI, was measured using questions adapted from existing measures investigating sources of health- and nutrition-related information. Outcome measures, diet quality and dietary restraint, and mediator variables nutrition knowledge, confusion, backlash, and social comparison were measured using established measures. Mediation analyses were conducted using path analysis. One hundred and eleven young adults (55.5%) reported using SMNI at least once within the last year and 93 (46.5%) within the last month. Recipes was reported as the main reason for use. Use of SMNI within the last month was positively associated with nutrition knowledge (β = 0.19 [95% CI: 0.06, 0.32]), which was positively associated with diet quality (β = 0.25 [95% CI: 0.12, 0.38]). There was a positive indirect effect between SMNI and diet quality, via nutrition knowledge (Ind = 0.05 [95% CI: 0.01, 0.09]), providing evidence of mediation. Nutrition confusion was positively associated with backlash (β=0.46 [95% CI: 0.34, 0.59]), which was negatively associated with diet quality (β = −0.31 [95% CI: −0.47, −0.15]). Use of SMNI was not significantly associated with restrained eating. Almost half of the young adults in this study reported use of SMNI at least once in the last month and recipes was the most common type of information sought. This finding is consistent with the literature(2,3) and indicates that social media is a popular source of nutrition-related information and recipe content among young adults. SMNI was positively associated with diet quality and was mediated by nutrition knowledge. These findings suggest that social media may be an important tool to distribute high quality nutrition-related information and for nutrition promotion aimed at young adults, however, experimental research is required to investigate causal pathways. The growth and ubiquity of social media and its potential for effective and wide-reaching nutrition promotion highlight social media as a priority area for research in the field of public health nutrition and aligns with the priority area outlined in the Decadal Plan for the Science of Nutrition to harness the reach of social media for nutrition promotion(4).