This study aims to examine how the sociodemographic and professional characteristics of nurses in Jordan correlate with their levels of knowledge, attitudes, and ageism toward older adults. Ageism has not been studied in Jordan as it pertains to nurses, so a descriptive, correlational, cross‐sectional design, with a convenience sample of 317 Jordanian nurses, using the Fact on Aging Quiz 1, Fraboni Scale of Ageism, and Relating to Older People Evaluation was conducted in January to February 2019. Significant ageism was found, and differences in knowledge, attitudes, and negative ageism vary among nurses by sociodemographic/professional characteristics. Knowledge and attitudes toward older adults significantly correlate with negative ageism which is associated with poor health outcomes for older adults. Our findings reveal that even in a country with high religious observance and close family ties, ageism exists in healthcare settings because of nurses' poor knowledge and attitudes toward older adults. These findings have implications for nursing education, clinical practice, and health policy. Changes across these sectors based on the findings may contribute to reducing ageist practices and improving older adult health outcomes.