As the world becomes more globalized and socially connected, challenges associated with diversity and disparities are taking center stage in the field of aging. Aging is no longer viewed as a biological monolith but one that is underpinned and buttressed by constructs like equity, accountability, access, and inclusion. The need for research to examine diversity and disparities among healthy and clinical populations is reflected in the recent literature. Brewster et al. (2019) discussed the importance of adopting a systems-level approach (e.g., National Institute on Aging [NIA] Health Disparities Research Framework) to identify mechanisms and pathways that reinforce health disparities. Babulal et al. (2019) proposed recommendations for prioritizing and advancing recruitment of racial and ethnic minorities in Alzheimer’s disease and related dementia (ADRD) research. Fredriksen-Goldsen and colleagues (2018) elaborated on core competencies required to care for older LGBT (lesbian, gay, bisexual, and transgender) older adults living with cognitive impairment and ADRD. These perspectives and position papers originating from national conferences and working groups call for aging studies to better inform diversity and disparities research. This Special Issue of Journal of Applied Gerontology includes 12 articles that employ a spectrum of quantitative, qualitative, and mixed methodologies to critically examine the intersectionality of nationality, race, ethnicity, and LGBTQ orientation (lesbian, gay, bisexual, transgender, and queer) surrounding diversity and disparities among older adults.