Introduction: This study examines caregiver quality of life (CQOL) 3–26 years after autologous hematopoietic cell transplantation (HCT) for patients with lymphoma. Using a framework that views the patient-caregiver dyad as a system of mutual influence, we argue that CQOL is associated with survivor functional health status and sense of personal control. Methods: Ninety-nine autologous HCT survivor-caregiver dyads participated. CQOL was measured using the Caregiver Quality of Life Scale-Cancer. Survivor functional health status was assessed using the Functional Assessment of Cancer Therapy-General. Sense of control was examined using an instrument from the MIDUS II study. Clinical measures were collected from medical records. Results: After controlling for sociodemographic and clinical covariates, caregivers with higher sense of control had higher CQOL. Poorer survivor functional health was associated with lower CQOL but only when the survivor reported low personal control. When the survivor reported high personal control, functional health was not a factor. Lower CQOL was observed for younger and more educated caregivers. In contrast, more education among survivors was linked to higher CQOL. Conclusion: These results (1) support using a mutuality framework for the study of long-term outcomes of caregivers, (2) suggest the importance of ongoing support for caregivers, and (3) help identify caregivers at risk for poorer adaptation. Poorer survivor functional health is a risk factor, but its adverse implications can be offset by higher caregiver and survivor sense of control, a psychological resource aiding caregiver adaptation. These findings can inform the development of support programs for long-term caregivers.