Purpose: To identify factors associated with resilience in primary caregivers of patients with advanced oral cavity cancer within the first 6 months post‐treatment. Design: A cross‐sectional study. Methods: We recruited patient–primary caregiver dyads from the outpatient radiation department of a medical center in Northern Taiwan. Patients were assessed using a set of structured questionnaires to measure performance status and demographic and clinical characteristics. Primary caregivers were measured in their social support, resilience, and care characteristics. Results: Of the 148 dyads surveyed, 33.8% of primary caregivers reported moderately low to moderate resilience, and 61.5% reported low resilience. Greater resilience of primary caregivers was associated with the primary caregiver factors of younger age, lower educational level, and more affectionate social support; and greater resilience was associated with the patient factors of better performance status and older age. These factors explained 40.4% of the variance in resilience. Conclusions: Patients' performance status and primary caregivers' affectionate social support strongly influence overall resilience and each domain of resilience. Clinical Relevance: Providing primary caregivers with sufficient social resources and a support group can help them cope with the demands of caregiving for loved ones with oral cavity cancer.