Given the distinct health risks Black women face, which are largely due to their marginalized status as both women and Black within the context of gendered racism, scholars have increasingly considered the role of culturally-relevant coping in shaping the distinct health patterns of this group. One form of coping that may have particular significance for Black women’s health is John Henryism , defined as persistent and high effort active coping with psychosocial and environmental stressors. John Henryism reflects the broader societal, cultural, and historical context that shapes the lived experiences of Black populations navigating racism and capitalism in the U.S. Overall, high-effort coping can be physiologically strenuous, contributing to increased stress on the body that eventually results in poor physical health, while simultaneously helping individuals to effectively manage stressful experiences. Although John Henryism has been linked to both mental and physical health, it has been primarily studied among Black men. Despite evidence demonstrating that ethnicity shapes health processes, ethnicity has not been widely considered in health-focused research on John Henryism with Black women. Therefore, the purpose of this dissertation was to evaluate how John Henryism shapes mental and physical health among African American and Caribbean Black women. This dissertation was a secondary analysis of the National Survey of American Life (NSAL 2001-2003), with an analytic sample of 1,580 Black women (1,209 African American women and 371 Caribbean Black women). 80% of the Caribbean Black women were U.S. born. Key measures for this dissertation included: mental health indicators (i.e., psychological distress, self-rated mental health, depressive symptoms, past-year major depressive disorder); physical health indicators (i.e., self-rated health, chronic health conditions), John Henryism, ethnicity, stress exposure indicators (i.e., chronic stress, everyday discrimination, goal-striving stress), and sociodemographic characteristics (i.e., age, SES). Logistic, multinomial logistic, and negative binomial regression were used. Findings indicate that John Henryism is seemingly harmful for the mental health of Black women overall, but protective for Caribbean Black women, while being largely neutral for the physical health of Black women overall but harmful for Caribbean Black women in particular.