The missionary position is a man on top sex position in which the woman lies on her back and the partners face each other. Variations of the position allow different degrees of vaginal tightness, clitoral stimulation, depth of penetration, participation on the part of the woman, and likelihood and speed of orgasm. These variations may involve the woman resting her feet on the bed, lifting them up high into the air, or wrapping them around her partner; or placing one or more pillows under the woman's buttocks.

The missionary position was advocated by Thomas Aquinas and other church figures in medieval Europe. It appears in ancient artwork of the Romans, Peruvians, Indians, Chinese and Japanese. In Sirach it is asserted that Adam quarreled with his first wife Lilith because she would not submit to his always being on top during sex, while Eve did submit to that.

A common myth states that the term "missionary position" arose in response to Christian missionaries, who taught that the position was the only proper way to engage in sexual intercourse. This explanation probably originated from Alfred Kinsey's Sexual Behavior in the Human Male through a confluence of misunderstandings and misinterpretations of historical documents.Tuscans refer to the position as "The Angelic Position" while some Arabic-speaking groups call it "the manner of serpents."

The missionary position is often preferred by couples who enjoy its romantic qualities afforded by copious skin-to-skin contact and opportunities to look into each other's eyes and kiss and caress each other. The position is also believed to be a good position for procreation. In heterosexual sex, missionary allows the man to take charge of the rhythm and depth of thrusting, and some couples enjoy the feeling of the man "taking" the woman while she relaxes. It is also possible for her to thrust against him by moving her hips or pushing her feet against the bed, or squeeze him closer with her arms or legs. The missionary position is less suitable for late stages of pregnancy, or when it is desired for the woman to play a more dominant role.