Background: National Cancer Institute (NCI) and nonprofit organization (NPO) funding is critical for research and advocacy, but may not be equitable across cancers or racial and ethnic groups. Methods: This study evaluated funding from the NCI and NPOs supporting lung, breast, colorectal, pancreatic, hepatobiliary, prostate, ovarian, cervical and endometrial cancers, leukemia, lymphoma and melanoma from 2015-2018. The primary objectives were to assess for disparities in NCI and NPO funding across different cancers compared to their incidence and mortality and their incidence rates across age, racial and ethnic groups. We also investigated if underfunding correlates with fewer clinical trials. Correlations between NCI and NPO funding for each cancer and its incidence, mortality and number of clinical trials were analyzed using scatter plots and Pearson correlation coefficients (PCCs). Results: Diseases with the largest combined NCI and NPO funding were breast cancer ($3.75 billion) and leukemia ($1.99 billion). Those with the least funding were endometrial ($94 million), cervical ($292 million), and hepatobiliary cancers ($348 million). Disease-specific funding correlated well with incidence, but correlated poorly with mortality (PCCs: 0.74, p = 0.006 and 0.30, p = 0.346, respectively). Breast cancer, leukemia and lymphoma were consistently well-funded, while colorectal, lung, hepatobiliary and uterine cancers were consistently underfunded. These data are summarized in the Table. NCI and NPO funding increased proportionately as incidence increased for White patients (PCC: 0.73, p = 0.007), Hispanic patients (PCC: 0.66, p = 0.02), Asian/Pacific Islanders (PCC: 0.77, p = 0.003) and Native Americans and Alaskans (PCC: 0.72, p = 0.008) while cancers with higher incidence in the Black population were underfunded (PCC: 0.52, p = 0.08). The amount of combined NCI and NPO funding for a particular cancer correlated strongly with the number of clinical trials for that disease (PCC: 0.91, p < 0.0001). Conclusions: Many cancers with high incidence and mortality are underfunded, including those with higher incidence among Black patients. Underfunding strongly correlates with fewer clinical trials, which could impede future advances in underfunded cancers.