Chronic insomnia (more than three months duration) is a common and significant health problem which impacts negatively on mental and physical health, quality of life, and is associated with increased healthcare utilisation costs. Cognitive behavioural therapy for insomnia (CBTi) is an effective non-drug intervention. General practitioners commonly manage patients with insomnia but lack the time and referral options to either provide or refer patients for CBTi. These issues are compounded in rural and regional areas where mental health professionals such as psychologists are in short supply. In this context, use of sedative/hypnotic medications that can cause dependence and have adverse effects is common. Use of digital CBTi may be an option for providing low cost and accessible treatment but there is a need for evidence on effectiveness and whether clinician support and follow-up is needed.The study aims to compare two methods of delivering digital CBTi for chronic insomnia in primary care, with usual care (sleep hygiene advice).The research plan has been co-designed with consumers and representatives of professional associations. In a three-arm cluster randomised controlled trial we compare the effectiveness and cost effectiveness of; 1) self-guided digital CBTi (access to an interactive digital CBTi program without GP support), 2) clinician-guided digital CBTi (digital CBTi + individualised onboarding and follow-up support from GPs), and 3) augmented usual care control (sleep hygiene advice, provided digitally).Patient outcomes assessed will include insomnia severity, depression, and use of sedative/hypnotic medication. A process evaluation will explore experience of the interventions from the perspectives of consumers and health professionals.The poster presentation will describe the intervention and study design. To date 33 GPs from 24 rural and regional general practices have agreed to take part in the study. The first block of 6 practices will be randomised in early 2026.The study will explore whether digital CBTi is acceptable to people living in regional and rural locations, whether it is more effective than digital sleep hygiene advice, and the extent to which GP involvement increases uptake and effectiveness.