Background <p>Family caregivers play a critical role in the recovery and rehabilitation of patients undergoing total knee arthroplasty (TKA). Despite this importance, research on family caregiver support is fragmented and lacks a structured framework that accounts for the evolving nature of family caregiver responsibilities over time.</p> Aim <p>To map the current evidence on support for family caregivers of patients undergoing TKA, using a modified “Timing It Right” theory framework to categorize family caregivers’ needs across different stages of the surgical trajectory.</p> Methods <p>This scoping review was conducted in accordance with JBI scoping review methodology. Peer-reviewed studies published between 2010 and 2025 were retrieved from PubMed, CINAHL, Scopus, Web of Science, and Embase. Studies were included if they addressed family caregiver support in the context of TKA and reported relevant outcomes. Findings were synthesized and categorized into four phases: Event/Diagnosis and Stabilization, Preparation, Implementation, and Adaptation.</p> Results <p>Nineteen studies involving 1,822 caregivers and 1,878 patients were included. Most studies emphasized appraisal (84%) and informational support (58%), while emotional and training support were underrepresented. Support delivery varied across hospital, outpatient, and home settings. Only four studies implemented structured caregiver interventions. Caregiver needs were infrequently assessed or used to tailor support. The Adaptation phase was least addressed. Few studies evaluated intervention effectiveness longitudinally or included diverse populations.</p> Conclusion <p>Current evidence highlights critical gaps in caregiver support, especially in personalization, emotional care, and long-term follow-up. Future research should focus on developing theory-based, phase-specific, and culturally sensitive interventions to strengthen caregiver involvement in TKA rehabilitation.</p> Clinical trial number <p>Not applicable.</p>