This longitudinal cohort study examined changes in illness perceptions, coping strategies, and quality of life in hospitalized participants who had sustained extremity injuries, and examined the associations among these changes. A sample of 138 patients with extremity injuries was recruited between August 2019 and April 2020 from the trauma units of two similar referral medical centers, each with a capacity of over 200 beds in Surabaya City, Indonesia. Outcome measures were assessed prior to hospital discharge and 3 months post-discharge, including the Brief Illness Perception Questionnaire, the Brief Coping Orientation to Problems Experienced, and the World Health Organization Quality of Life. Hierarchical multiple regression analyses were conducted. We found that lower scores for illness perceptions (i.e., how a participant appraised and understood their medical condition and its possible consequences) and maladaptive coping strategies were significantly associated with lower quality of life scores. In addition, scores for adaptive coping strategies moderated the association between illness perceptions and quality of life. Our findings suggest that clinicians should endeavor to improve patients' illness perceptions and adaptive coping strategies during the first 3 months post-injury to promote improvement in quality of life following extremity injury.