Unhealthy food environments are major drivers of obesity and diet-related diseases(1). Improving the healthiness of food environments requires a widespread organised response from governments, civil society, and industry(2). However, current actions often rely on voluntary participation by industry, such as opt-in nutrition labelling schemes, school/workplace food guidelines, and food reformulation programmes. The aim of the REFORM study is to determine the effects of the provision of tailored support to companies on their nutrition-related policies and practices, compared to food companies that are not offered the programme (the control). REFORM is a two-country, parallel cluster randomised controlled trial. 150 food companies were randomly assigned (2:1 ratio) to receive either a tailored support intervention programme or no intervention. Randomisation was stratified by country (Australia, New Zealand), industry sector (fast food, other packaged food/beverage companies), and company size. The primary outcome is the nutrient profile (measured using Health Star Rating [HSR]) of foods and drinks produced by participating companies at 24 months post-baseline. Secondary outcomes include company nutrition policies and commitments, the nutrient content (sodium, sugar, saturated fat) of products produced by participating companies, display of HSR labels, and engagement with the intervention. Eighty-three eligible intervention companies were invited to take part in the REFORM programme and 21 (25%) accepted and were enrolled. Over 100 meetings were held with company representatives between September 2021 and December 2022. Resources and tailored reports were developed for 6 touchpoints covering product composition and benchmarking, nutrition labelling, consumer insights, nutrition policies, and incentives for companies to act on nutrition. Detailed information on programme resources and preliminary 12-month findings will be presented at the conference. The REFORM programme will assess if provision of tailored support to companies on their nutrition-related policies and practices incentivises the food industry to improve their nutrition policies and actions.