Background <p>More than half of individuals with chronic pain also experience insomnia. Cognitive behavioral therapy for insomnia (CBT-I) is an effective and safe first-line treatment; however, access remains a major barrier to widespread implementation. This study aims to evaluate the effectiveness of a 9-week app-delivered CBT-I intervention, compared to an app-delivered sleep hygiene education program (active control), in reducing insomnia and pain severity in patients with disabling chronic pain and comorbid insomnia.</p> Methods <p>The trial is a 1:1 randomized, single-blind, superiority trial randomizing 160 patients with disabling chronic pain and comorbid insomnia to either app-delivered CBT-I for 9 weeks or app-delivered sleep hygiene education for 9 weeks. Primary outcomes are the between-group differences in change in Insomnia Severity Index (ISI) and average pain intensity assessed using a 0–10 numeric rating scale (NRS) from baseline to post-interventions. Short-term secondary outcomes post-intervention include perceived effects on sleep and pain (Global Perceived Effect scales), sleep quality, thoughts and beliefs about sleep and pain, physical and mental health, and EQ5D-5L. Medium-term and long-term secondary outcomes (ISI, pain intensity, EQ5D-5L, health care costs, and use of sleep and pain medication) will be collected after 24 and 52 weeks. Exploratory physiological sleep metrics from at-home ear-electroencephalography (EEG) will be collected for five nights at baseline and for five nights during week 8.</p> Discussion <p>This planned study addresses a critical need for identifying effective, safe, and easily accessible alternatives to the current treatments for patients with chronic pain and insomnia.</p> Trial registration <p>ClinicalTrials.gov NCT06361914. Registered on April 17, 2024.</p>