A generation gap describes a vast difference in cultural norms between a younger generation and their elders. According to the dictionary definition by freesearch, the generation gap (noun) occurs when older and younger people do not understand each other because of their different experiences, opinions, habits and behaviour. [Cited from http://www.freesearch.co.uk/dictionary/the+generation+gap]

The term first came into prominence in Western countries during the 1960s and described the cultural differences between the baby boomers and their parents. Although history had always seen some degree of generational differences, during this era the differences between the two generations magnified significantly in comparison to previous times. There were major differences in such matters as musical tastes, fashion, drug use, and politics. This situation may have been accelerated by the unprecedented size of the young baby boomer generation, which gave them a greater sense of power and influence than had been seen previously, and the younger generation was willing to rebel against society norms to an previously unseen degree.

Several examples of generational differences were prominent during the period. Rock music and soul music, popular among the youth, was mostly detested by their elders. Long hair on young males was frequently seen as a shocking act of rebellion against societal norms by their parents. The large scale protests against the Vietnam War on American college campuses contrasted sharply with the universal national support for World War II that their parents had experienced. Traditional sexual mores were crumbling under the weight of the sexual revolution. Drug use increased among young people, and many youths "dropped out" into the hippie counterculture. While not all of these attributes characterized all young people, the differences were pervasive enough among enough people to cause significant friction in many areas of society.

Baby boomers had a strong sense of generational identity during this period. A common catchphrase of the era among young people was "don't trust anyone over 30." This sentiment was also expressed by The Who, in their anthem "My Generation", in which the narrator sang, "Hope I die before I get old." The influence of the baby boomers was so significant that the entire generation was named "Man of the Year" by Time magazine in 1966.

In the 1980s, and even more so the 1990s, many have made note of a widening rift between the Baby Boomers and Generation X, with the latter often accusing the former of having "sold out" their 1960s-era ideals and advocating a moral crackdown on the latter's allegedly wild, undisciplined behavior. This theme became an important element in what some commentators have labelled the Culture Wars.

In the both the aforementioned case and the earlier conflict, another generation is often seen as standing in between the two engaged in argument, either identifying with both side's assertions or neither's. In the 1960s the Silent Generation was frequently described as the group filling this role, with the Baby Busters occupying a similarly intermediate position in the more recent Baby Boomer-Generation X feud.

Despite the sharp divides between generations, cross-generational friendships and cross-generational sexual relationships are common.