Despite higher risks of developing Alzheimer's disease and Alzheimer's disease-related dementias (AD/ADRD) among racial/ethnic minority populations, some maintain good cognition until old age. This study aimed to investigate heterogeneous cognitive trajectories among non-Hispanic Black and Hispanic older adults, examine cognitive impairment prevalence across trajectory classes, and identify associated social and behavioral determinants. Using 11 waves of data from the Health and Retirement Study (1996-2016), 1,322 non-Hispanic Black and 747 Hispanic adults aged 50 + with normal cognition in 1996 were included. Latent class growth modeling and multinomial logistic regressions were performed to examine cognitive trajectories and associated determinants. For both racial/ethnic groups, three trajectory classes were identified: high, medium, and low cognition. In the low cognition class, 87% and 100% of non-Hispanic Black and Hispanic participants developed cognitive impairment. For both racial/ethnic groups, older age and living in rural areas during school time increased the likelihood of being in the low cognition class, while more education was associated with a lower likelihood. Unique risk and protective determinants for non-Hispanic Black and Hispanic participants were also identified. This study reveals the heterogeneity of cognitive trajectories among racial/ethnic minority older adults and various associated social and behavioral determinants. More prevention interventions and accessible, affordable diagnosis and treatment should be provided to older racial/ethnic minorities with these characteristics to reduce disparities. More research is needed to further explore associations between unique determinants and cognition in racial/ethnic minority populations to better inform interventions.