The World Health Organisation reports significant weight gain was observed throughout the COVID-19 lockdowns, potentially fuelled by lifestyle changes from increased social isolation, food supply chain disruption, and heightened demand for unhealthy foods.⁽¹⁾ Food accessibility was considerably impacted by stay-at-home orders, leading to a rise in online food purchasing platforms for contact-free delivery of groceries, takeaway meals and meal-kits. The aim of this systematic review was to assess the use of online food purchasing platforms during COVID-19. A secondary aim was to observe any associated dietary behaviours with the use of online food delivery services and determine their impact on health outcomes. Nine electronic databases were searched. Cross-sectional, qualitative and mixed-methods studies published in peer-reviewed journals between January 2020 and April 2022 were included. A total of 55 articles were included in this review. Studies conducted in the second quarter of 2020 (April to June) comprised of 47% of all included articles. Half of relevant study findings were reported from high-income countries according to the World Bank classification. Over a third (35%) of included studies had a majority young adult population aged between 18-30 years. Overall, online grocery shopping was shown to be widely adopted, with 53/60 findings supporting the usage of such services during COVID-19 lockdowns. While 26 findings favoured usage of online food delivery during lockdown, 25 findings reported a decrease in these meal delivery applications. Two studies reported an increase in meal-kit delivery services which offer the delivery of ingredients prepared for a meal plan. Eight studies reported on diet and health outcomes associated with online food delivery use. Six findings reported negative diet and health outcomes, two were positively impacting diet and one study was found to have mixed effects. As lockdowns resulting from the COVID-19 pandemic have threatened food accessibility, it is critical to understand how online food retail platforms have been used by populations across the world. This review demonstrates a surge in the adoption of online food platforms, indicating their potential long-lasting and high impact on health. The digital food environment requires further investigation and monitoring.