Objective: Diet-related apps and websites are developed to help improve dietary intake. The aim of this study is to explore the use and acceptability of diet-related apps and websites in Australia. Methods: In a cross-sectional study, 241 participants (mean age = 40.6 years) completed an online survey about demographic characteristics, lifestyle behaviours and health concerns, experience and confidence in technology use, and preferences, attitudes and perception of diet app and website use. Descriptive analysis and unadjusted multiple logistic regression were used to explore data. Results: Overall, 63.5% of participants were current or previous app users. App users were more confident in using technology, more concerned about diet and weight, and more trusting of information provided in diet-related apps compared to non-app users (p ≤.05). Features such as food tracking, nutrient check and barcode scanning were preferred by both users and non-users. The likelihood of using diet-related apps was higher for those who trust the app information (OR 5.51, 95%CI: 2.40–12.66), often count calories (OR 2.28, 95%CI: 1.01–5.24) and are often on diet (OR 4.16, 95% CI: 1.21–14.21) compared to their counterparts. Conclusions: More than half of the Australians that participated in this study used diet-related apps and websites. App features that allow the user to accurately record and monitor food intake and scan barcodes may motivate app use. Future public health strategies may take advantage of diet-related apps and websites to improve dietary behaviour at the population level and reduce the burden of obesity and non-communicable diseases.