Sexual response refers to the set of physiological and emotional changes that lead to and follow orgasm. Different researchers have constructed various models.

Usually, these models include three, four, or five distinct phases, with the exact components of each phase differing across models.

Helen Singer Kaplan proposed the Triphasic Concept of human sexual response involving three stages: desire, excitement, and orgasm. In his book "Human Sexual Response", Lief described five sexual response phases: desire, arousal, vasocongestion, orgasm, and satisfaction.

William Masters and Virginia Johnson, prominent sex researchers and therapists, suggested that there are four identifiable phases in the sex response cycle: excitement, plateau, orgasm, and resolution.

Using various instruments designed to monitor changes in heart rate and muscle tension, Masters and Johnson were able specify the bodily changes that characterize each of these phases.