Individuals with severe mental illness (SMI) have higher mortality rates from cancer than individuals without SMI. The aim of this paper is to highlight these disparities in cancer care in individuals with SMI and suggest potential solutions. We conducted a narrative review of published papers, focusing on mortality, incidence, behavioral and provider risk factors, screening, diagnosis, treatment, and palliative care among individuals with SMI and cancer. The literature does not provide a clear consensus on whether a difference in cancer incidence exists among individuals with SMI compared to the general population. However, it is evident that individuals with SMI have higher mortality from cancer. Factors such as increased cancer related risk behavior, mental health stigma, and difficulty accessing cancer care contribute to this mortality difference. The literature also indicates lower screening rates, delayed and improper diagnosis and treatment, as well as inadequate clinical trial enrollment in individuals with SMI. While the literature is inconclusive regarding disparities in palliative care, we outline key concepts to provide the best possible end of life care to this population. We also summarize strategies to address disparities at the screening, diagnostic, and treatment levels and describe general strategic approaches to improve cancer care in individuals with SMI. We highlight patient-related, physician-related, and healthcare/systems-related factors leading to disparities in cancer care in individuals with SMI. Future research must examine the effectiveness of proposed solutions to guide evidence-based practices.