The population of older adults with cancer in the United States is rapidly increasing, which will have a substantial impact on the oncology and public health workforces across the cancer continuum, from prevention to end of life. Unfortunately, inequities in existing social structures that cause increased psychosocial stressors have led to disparities in the incidence of cancer and the morbidity and mortality of cancer for individuals from marginalized backgrounds. It is imperative that older adults, especially those from historically marginalized backgrounds, be adequately represented in all stages of cancer research to address health inequities. Continued efforts and progress toward achieving social justice and health equity require a deeper commitment to and better understanding of the impact of social determinants of health within the cancer domain. Undoubtedly, a more holistic and integrated view that extends beyond the biologic and genetic factors of health must be adopted for health entities to recognize the critical role of environmental, behavioral, and social determinants in cancer health disparities. Against this backdrop, this paper uses a life course approach to present a multifactorial framework for understanding and addressing cancer disparities in an effort to advance social justice and health equity for racially and ethnically diverse older adults.