Few studies examine how cancer caregiving stress "proliferates," or how stress related to care provision spreads and influences other aspects of life. These other aspects of life are called secondary stressors and may include perceptions of family support, financial strain, or the caregiver's schedule. In the current study, data on sociodemographic background, care demands, and psychosocial stress were collected from 186 cancer caregivers. A multivariate regression analysis was used to identify factors reliably related to secondary stressors. Role overload appeared to exacerbate multiple secondary stressors, whereas socioemotional support protected caregivers against all dimensions of secondary stress. These empirical results are among the first on predictors of secondary stress in cancer caregiving, and they may inform future descriptive and clinical examinations of the stress process in cancer caregiving families.