Masturbation is the sexual stimulation of one's own genitals for sexual arousal or other sexual pleasure, usually to the point of orgasm. The stimulation may involve hands, fingers, everyday objects, sex toys such as vibrators, or combinations of these. Mutual masturbation is masturbation with a sexual partner, and may include manual stimulation of a partner's genitals (fingering or a handjob), or be used as a form of non-penetrative sex.

Masturbation is frequent in both sexes and at any age. Various medical and psychological benefits have been attributed to a healthy attitude toward sexual activity in general and to masturbation in particular. No causal relationship is known between masturbation and any form of mental or physical disorder. Masturbation is considered by clinicians to be a normal and healthy part of sexual enjoyment. Today, religions vary in their views of masturbation; some view it as a spiritually detrimental practice, some see it as not spiritually detrimental, and others take a situational view.

Masturbation has been depicted in art since prehistoric times, and is both mentioned and discussed in very early writings. In the 18th and 19th centuries, some European theologians and physicians described it in negative terms, but during the 20th century, these taboos generally declined. There has been an increase in discussion and portrayal of masturbation in art, popular music, television, films, and literature. The legal status of masturbation has also varied through history and masturbation in public is illegal in most countries. Animal masturbation has been observed in many species, both in the wild and in captivity.