Objective The aim of this study was to identify factors associated with unmet supportive care needs in family caregivers of patients with oral cancer after surgery. Methods In a cross‐sectional study, we recruited patient–family caregiver dyads from the otolaryngology head and neck surgery wards of a medical center in northern Taiwan. Patients were assessed using a set of structured questionnaires to measure symptom distress, sleep quality, and depression. Social support and supportive care needs of family caregivers were measured. Results Of the 102 dyads surveyed, needs for supportive care in information domain and healthcare professional/healthcare services domain were highest. Patients with more severe symptoms and family caregivers who received less social support from family were associated with greater overall unmet supportive care needs. Conclusions Family caregivers report the need for more information and healthcare services after a family member has had oral surgery. Caregiving training programs should be developed for caregivers on the basis of meeting reported needs. Copyright © 2014 John Wiley & Sons, Ltd.