With the increasing population of older adults, ageism is an obstacle to health equity and can negatively affect older adults' quality of life and nursing care. This study aims to examine the level of ageism and the factors associated with ageism among nursing college students, who will become the main workforce for gerontological nursing. A cross-sectional survey was conducted among 238 nursing students in two nursing colleges in South Korea. The total score for ageism was 37.06 (SD 5.94) out of a maximum of 72. In the multiple regression model, the predictors of ageism were aging anxiety (β = 0.420, p < 0.001), frequency of contact (β = -0.204, p < 0.001), preference for gerontological nursing (β = 0.150, p = 0.003), age (β = 0.145, p = 0.003), and quality of contact (β = -0.143, p = 0.030), revealing that these were factors influencing ageism in the evaluated nursing students. The results suggest that tailored gerontological education programs or community link programs in the nursing curriculum are necessary to share feelings of contact, increase positive experiences with older adults, and reduce anxiety about aging.