Asexuality (sometimes referred to as nonsexuality), in its broadest sense, is the lack of sexual attraction to others or the lack of interest in sex. It may also be considered a lack of a sexual orientation. One commonly cited study published in 2004 placed the prevalence of asexuality at 1%.

Asexuality is distinct from abstention from sexual activity and from celibacy, which are behavioral and generally motivated by factors such as an individual's personal or religious beliefs; sexual orientation, unlike sexual behavior, is believed to be "enduring". Some asexual people do engage in sexual activity despite lacking a desire for sex or sexual attraction, due to a variety of reasons, such as a desire to please romantic partners or a desire to have children.

Only recently has asexuality started to become accepted as a sexual orientation and a field of scientific research, and a growing body of research from both sociological and psychological perspectives has begun to coalesce. While some researchers assert that asexuality is a sexual orientation, others disagree, and various asexual communities have started to form since the advent of the Internet and social media. The most prolific and well-known of these communities has been the Asexual Visibility and Education Network (AVEN), which was founded in 2001.