Old age is the range of ages for people nearing and surpassing life expectancy. People of old age are called old people , the elderly , elders , senior citizens , seniors , or older adults. Old age is not a definite biological stage: the chronological age denoted as "old age" varies culturally and historically. Some disciplines and domains focus on the aging and the aged, such as the organic processes of aging (senescence), medical studies of the aging process (gerontology), diseases that afflict older adults (geriatrics), technology to support the aging society (gerontechnology), and leisure and sport activities adapted to older people (such as senior sport).

Old people often have limited regenerative abilities and are more susceptible to illness and injury than younger adults. They face social problems related to retirement, loneliness, and ageism.

In the United States, a 2023 national poll found that about 37% of older adults aged 50 to 80 experienced loneliness, and 34% reported feeling socially isolated. In response to loneliness among older adults, many nonprofit organizations in North America and the United Kingdom provide companionship through volunteer home visits, phone calls, letters, group activities, and other programs. See also Category:Gerontology organizations and Category:Charities for the elderly.

In 2011, the United Nations proposed a human-rights convention to protect old people.