Early maladaptive schemas represent unhelpful frameworks of cognitions, emotions and subsequent behavioural responses and can be associated with depressive symptoms. Caregivers of individuals with serious mental illness (SMI) frequently report experiencing depressive symptoms. It is unclear whether depressive symptoms in caregivers are influenced by schemas. We aimed to compare activated schemas in caregivers of people with schizophrenia spectrum (SSD) and bipolar disorder (BD) diagnoses and to determine whether they were differentially related to depressive symptoms. Caregivers completed validated measures of depression and schemas. Independent samples t-tests and multivariate generalised linear models were used to assess differences in schemas and depressive symptoms between caregiver groups. Interrelationships between schema domains and caregiver depressive symptoms were delineated using correlational analyses and forward stepwise regressions. One hundred eight caregivers participated in the study (SSD n = 68, BD n = 40). No differences in depressive symptom severity or activated schemas were observed between caregiver groups. All schemas were significantly associated with depressive symptoms, and the Disconnection-Rejection schema domain explained the most variance in depressive symptoms in both caregiver groups. Schemas contribute to the severity of caregiver depression regardless of whether the person receiving care is diagnosed with SSD or BD. Schema therapeutic frameworks may be beneficial for use with caregivers to address schemas within the Disconnection-Rejection domain and alleviate depressive symptoms by reducing experiences of social isolation and alienation.