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.

Fear of children, fear of infants or fear of childhood is alternatively called pedophobia (American English), paedophobia or pediaphobia. Other age-focused fears are ephebiphobia and gerontophobia. Recognised outcomes of pedophobia include paternalism, adultism, and by extension, ageism.

The word "pedophobia" comes from the Greek roots παιδ- "paid-" "child" and φόβος "-phóbos" "fear".

Media, marketers, politicians, youth workers and researchers have been implicated in perpetuating the fear of youth. Since young people in developed countries are expected to stay out of the workforce, any role for them outside that of consumer is potentially threatening to adults. Selling safety to parents and teachers has also been a driving force, as home security systems, cellphones, and computer surveillance usage is marketed to parents; and x-ray machines, metal detectors and closed-circuit television are increasingly sold to schools on the premise that young people are not to be trusted. These steps are in spite of the fact that experience consistently shows that monitoring youth does little to prevent violence or tragedy: the Columbine High School massacre occurred in a building with video surveillance and in-building police.

The very creation of the terms youth, adolescence and teenager have all been attributed to the fear of youth. As the western world became more industrialized, young people were increasingly driven from the workforce, including involuntary and voluntary positions, and into increasingly total institutions where they lost personal autonomy in favor of social control. Government policies outside of schools have been implicated as well, as over the last forty years curfews, anti-loitering and anti-cruising laws, and other legislation apparently targeted at teenagers have taken hold across the country. Courts have increasingly ruled against youth rights, as well. Before the 1940s "teenagers" were not listed in newspaper headlines, because as a group they did not exist. The impact of youth since World War II on western society has been immense, largely driven by marketing that proponents them as the "Other". In turn, youth are caused to behave in ways that appear different from adults. This has led to the phenomenon of youth, and in turn has created a perpetuated fear of them.