A sex organ or primary sexual characteristic, narrowly defined, is any of those parts of the body (which are not always bodily organss according to the strict definition) which are involved in sexual reproduction. They constitute the reproductive system in an complex organism. More generally and popularly, sex organs are those parts of the body involved in erotic pleasure.

The Latin term genitalia is used to describe the sex organs, and in the English language this term and genital area are most often used to describe the externally visible sex organs or external genitalia: in males the penis and scrotum, in females the vulva. The other parts of the sex organs are called the internal genitalia.

A gonad is an organ that produces gametes, specifically the testes or ovaries in humans.

The human sex organs are as follows.

Many parts of human sexual anatomy are homologous between the sexes: for example: See also: sex, human sexuality, sexual behavior, Obstetrics and gynecology, castration, intersex, transgender, intimate parts, genital mutilation, Wolffian ducts.