Ephebiphobia is the fear of youth. First coined as the "fear or loathing of teenagers", today the phenomenon is recognized as the "inaccurate, exaggerated and sensational characterization of young people" in a range of settings around the world. Studies of the fear of youth occur in sociology and youth studies. It is distinguished from pedophobia by being more focused on adolescents than prepubescent children.

Ageism is a bias against, discrimination towards, or bullying of individuals and groups on the basis of their age, younger or older. The term was coined in 1969 by Robert Neil Butler to describe discrimination against the elderly, patterned on the terminology of sexism and racism. Butler defined ageism as a combination of three connected elements: negative attitudes towards old age and the aging process, discriminatory practices against older people, and institutional practices and policies that perpetuate stereotypes about elderly people.