Background: A significant proportion of patients with chronic tinnitus reportclinical levels of sleep disturbance (insomnia). Despite the significant healthand functioning implications of this, no rigorous trials have investigated treatmentsthat target tinnitus-related insomnia. This is the first randomised controlledtrial evaluating Cognitive Behavioural Therapy for insomnia (CBTi) in tinnitus,compared to other psychological treatments. Methods: The study will test the efficacy of group CBTi as a treatmentfor tinnitus-related insomnia in a single-centre, randomised controlled trial. Participantswill be 102 patients with chronic, clinically significant tinnitus andinsomnia, in the absence of organic sleep disorders. Participants will be randomisedto one of three intervention arms: six sessions of CBTi or six sessions of Sleep Support Group or two sessions of Audiologically Based Care. The primary outcomeswill be changes in sleep as measured on the Insomnia Severity Index and keyoutcomes on a 2-week sleep diary (Sleep Efficiency and Total Sleep Time).Outcomes will be collected 3, 10, 14 and 34 weeks post-randomization. Secondarymeasures include sleep quality, sleep beliefs, tinnitus severity, psychologicaldistress and quality of life. Data on satisfaction and treatment experience willbe collected at 10 and 34 weeks post-randomization. A sub-sample ofparticipants will provide two weeks of actigraphy data at the same time points.Discussion: Findings from the studywill be submitted to a peer-reviewed journal. It is anticipated that findingsmay inform future clinical practice around treatment of tinnitus-relatedinsomnia. Trial Registration: Thetrial was with clinicaltrials.gov on 29 December 2017, RetrospectivelyRegistered (NCT03386123); URL(https://clinicaltrials.gov/ct2/show/NCT03386123?term=insomnia&cond=Tinnitus&rank=1).