Background: Family caregivers carry heavy end-of-life (EOL) caregiving burdens, with their physical and psychological well-being threatened from caregiving to bereavement. However, caregiving burden has rarely been examined as a risk factor for bereavement adjustment to disentangle the wear-and-tear vs relief models of bereavement. Objective/Methods Preloss and postloss variables associated with severe depressive symptoms and quality of life (QOL) for 201 terminally ill cancer patients' caregivers over their first 2 years of bereavement were simultaneously evaluated using multivariate hierarchical linear modeling. Severe depressive symptoms (Center for Epidemiological Studies Depression Scale score > 16) and QOL (physical and mental component summaries of the Medical Outcomes Study Short-Form Health Survey) were measured 1, 3, 6, 13, 18, and 24 months postloss. Results: Caregivers' likelihood of severe depressive symptoms and mental health-related QOL improved significantly from the second year and throughout the first 2 years of bereavement, respectively, whereas physical health-related QOL remained steady over time. Higher subjective caregiving burden and postloss concurrent greater social support and better QOL were associated with bereaved caregivers' lower likelihood of severe depressive symptoms. Bereaved caregivers' mental health-related QOL was facilitated and impeded by concurrent greater perceived social support and severe depressive symptoms, respectively. Conclusion: Severe depressive symptoms and mental health-related QOL improved substantially, whereas physical health-related QOL remained steady over the first 2 years of bereavement for cancer patients' caregivers. Timely referrals to adequate bereavement services should be promoted for at-risk bereaved caregivers, thus addressing their support needs and facilitating their bereavement adjustment.