<p>The lack of racial and ethnic diversity in samples used within the field of human genetics research has been well-documented. However, factors driving the under-representation of individuals who are not of European ancestry remains under-explored. The present study aimed to investigate whether willingness to participate in genetic research differed by race and ethnicity, as well as other demographic (e.g., age, gender, religion affiliation, education level) and psychological or individual factors (e.g., trust in research, knowledge of genetics, trait-level worry, health anxiety, altruism, health status) in two ethnically- and racially-diverse samples (<i>N</i> = 2000 via Prolific and <i>N</i> = 264 via an undergraduate psychology research pool). Participants indicated the types of research they would be willing to participate in, including providing saliva or blood samples for genetic research. Approximately, one third of participants endorsed willingness to provide a saliva sample, whereas one quarter endorsed willingness to provide a blood sample. Demographic factors associated with lower willingness included non-white racial/ethnic identities and lower income. Odds did not differ by age or gender identity. Mistrust of research was consistently associated with lower odds of providing a biological sample, whereas higher health anxiety, altruism, and the experience of a health condition was associated with higher odds of participation. Reasons for reluctance were explored, including the influence of compensation, additional information, opportunity for feedback, and study topic. Findings suggest that increasing transparency about how biological samples can be used, involving community leaders, and providing equitable compensation may increase engagement in genetic research, particularly among historically marginalized populations.</p>