BACKGROUND: Attention-deficit/hyperactivity disorder (ADHD) is a prevalent neurodevelopmental disorder that presents as early as preschool. Inattention and hyperactivity in childhood interfere with developing social and preacademic skills, leading to lifelong impairment. Evidence-based treatments for children with ADHD exist, including parent behavioral interventions (PBIs). However, current treatments have failed to substantially change the long-term trajectory of symptoms and impairment for individuals with ADHD, suggesting the need to enhance treatment approaches and intervene earlier. Given that sleep is a modifiable factor linked to ADHD symptom persistence and exacerbation, it may be a useful target in addressing ADHD among preschool children (ages 3-5 years). The most common sleep problems among preschoolers are behavioral and amenable to PBIs. However, sleep strategies have not been included within PBIs to address ADHD symptoms in young children. Thus, this pilot trial aims to assess the feasibility, acceptability, and appropriateness of a novel sleep-focused PBI (SF-PBI). Moreover, given the barriers to accessing care for sleep-related issues, this pilot trial aims to increase access to evidence-based care by partnering with behavioral health therapists embedded in pediatric primary care to deliver intervention. METHODS: A pilot randomized clinical trial is being conducted in 5 pediatric primary care offices by embedded behavioral health therapists with 50 families of 3- to 5-year-old children with elevated ADHD symptoms and behavioral sleep problems. Families are randomized (1:1) to six sessions of either standard PBI or SF-PBI, informed by focus groups with caregivers, therapists embedded in pediatric primary care, and pediatric providers. Primary outcomes at post-intervention will be therapist and caregiver report on the intervention's acceptability, appropriateness, and feasibility. DISCUSSION: Primary outcomes will inform the decision to transition to a definitive trial testing SF-BPI targeting sleep among preschool-aged children at elevated risk for ADHD via accessible, primary care-based intervention that harnesses parenting strategies. Ultimately, the SF-PBI has the potential to improve outcomes for children at risk for ADHD by increasing access to early intervention for behavioral sleep issues to reduce the prevalence, symptoms, and associated impairments of ADHD among children and families. TRIAL REGISTRATION: ClinicalTrials.gov NCT05683756 (prospectively registered, date registered 4 January 2023): https://clinicaltrials.gov/study/NCT05683756.