This study examined the role of patient and caregiver ambivalence over emotional expression (AEE) in pain and quality of life (QOL) in a sample of 78 patients with gastrointestinal (GI) cancer. Measures of ambivalence over emotional expression as well as ratings of patient pain and pain behavior were collected from patients and caregivers. Measures of pain catastrophizing, perceptions of social support, and QOL were obtained from patients. Data analyses revealed that patients high in AEE engaged in more catastrophizing and reported higher levels of pain behaviors and poorer QOL. In addition, patients whose caregivers were high in AEE engaged in more catastrophizing, had higher levels of pain and pain behavior, and reported lower emotional well-being. Patient catastrophizing mediated the effects of both patient and caregiver AEE on some patient outcomes. Taken together, these findings suggest that emotional regulation in both patients and their caregivers may be an important factor in understanding cancer patients' experience of and coping with symptoms such as pain.