老人学（英语：gerontology，也译作老年学）是指研究人类老化的生理层面、心理层面和社会层面等等。

老化泛指有机体一生中的所有变化。按其年龄，老人可以分为以下三类：

• 青老人（young-old）：65~74岁
• 中老人（old-old）：75~84岁
• 老老人（oldest-old）：85岁以上

Gerontology (from the Greek γέρων, geron, "old man" and -λογία, -logia, "study of"; coined by Ilya Ilyich Mechnikov in 1903) is the study of the social, psychological, cognitive, and biological aspects of aging. It is distinguished from geriatrics, which is the branch of medicine that specializes in the treatment of existing disease in older adults. Gerontologists include researchers and practitioners in the fields of biology, nursing, medicine, criminology, dentistry, social work, physical and occupational therapy, psychology, psychiatry, sociology, economics, political science, architecture, geography, pharmacy, public health, housing, and anthropology.