Premature ejaculation (PE) is the occurrence of ejaculation during sexual activity that a person cannot control, happening earlier than desired by the individual or their partner, usually shortly after vaginal penetration. This condition can lead to individual distress or interpersonal difficulties.

Researchers like Masters and Johnson defined premature ejaculation as 'the inability of the man to delay ejaculation until his partner reaches orgasm, and this condition being observed in a significant portion of sexual experiences.'

Current medical and psychological definitions typically emphasize the following characteristics:
* Ejaculation occurring consistently or recurrently approximately one minute after or earlier than vaginal penetration.
* A persistent or recurrent inability to delay ejaculation prior to or after vaginal penetration.
* This condition causing significant distress or interpersonal difficulties for the individual.