BACKGROUND: eHealth interventions can favorably impact health outcomes and encourage health-promoting behaviors in children. More insight is needed from the perspective of children and their families regarding eHealth interventions, including features influencing program effectiveness. OBJECTIVE: This review aimed to explore families' experiences with family-focused web-based interventions for improving health. METHODS: Five databases were searched on October 26, 2022-updated on October 24, 2023-for studies reporting qualitative data on participating children or their caregivers' experiences with web-based programs. Study identification was performed in duplicate and studies were independently appraised for quality. Thematic synthesis was undertaken on qualitative data extracted from the results section of each included article. RESULTS: Of 5524 articles identified, 28 articles were included. The studies examined the experiences of school-aged children (aged 5-18 years) and their caregivers (mostly mothers) with 26 web-based interventions that were developed to manage 17 different health conditions or influence health-supporting behaviors. Six themes were identified on families' experiences: connecting with others, agency of learning, program reputability or credibility, program flexibility, meeting participants' needs regarding program content or delivery, and impact on lifestyle. CONCLUSIONS: Families positively perceived family-focused web-based interventions, finding value in quality connections and experiencing social support; intervention features aligned with behavioral and self-management principles. Key considerations were highlighted for program developers and health care professionals on ways to adapt eHealth elements to meet families' health-related needs. Continued research examining families' experiences with eHealth interventions is needed, including the experiences of families from diverse populations and distinguishing the perspectives of children, their caregivers, and other family members, to inform the expansion of family-focused eHealth interventions in health care systems. TRIAL REGISTRATION: PROSPERO CRD42022363874; https://tinyurl.com/3xxa8enz.