A nocturnal emission is an ejaculation of semen experienced by males during sleep. It is also called a "wet dream".

Nocturnal emissions are most common during teenage and early adult years, and are the result of accumulated semen production. However, nocturnal emissions may happen any time after puberty, not just adolesence and early adulthood. They may or may not be accompanied by erotic dreams. Some males will wake during the ejaculation, while others will sleep through the event.

It is a common misconception that nocturnal emissions are the direct result of the stimulation caused by either erotic dreams or memories of waking sexual activities. For this reason the term is also used figuratively for something very pleasurable but often imagined or hoped for. In reality, nocturnal emissions occur without any type of stimulation.

The frequency of nocturnal emissions is highly variable. Some men have experienced large numbers of nocturnal emissions as teenagers, while some men have never experienced one in their lives. Contrary to popular belief, the frequency that one has Nocturnal emissions is completely unrelated to one's frequency of masturbation, as widely-known sex researcher, Alfred Kinsey claimed.

Whereas an ejaculation normally terminates an erection, in the case of noctural emission, the subject often still has a functional erection afterward.

Christian View

Saint Augustine held that nocturnal emissions did not pollute the conscience of an individual and were not voluntary carnal acts and were therefore not to be considered sinful. Augustine did, however, pray that he may be released from the "glue of lust" and thus recommended the beseechment of God's assistance in clearing one's soul of all such carnal affections.