Sadomasochism ( SAY-doh-MASS-ə-kiz-əm) is the giving and receiving of pleasure from acts involving the receipt or infliction of pain or humiliation. Practitioners of sadomasochism may seek sexual pleasure from their acts. While the terms sadist and masochist refer respectively to one who enjoys giving and receiving pain, some practitioners of sadomasochism may switch between activity and passivity.

The abbreviation S&M is commonly used for Sadomasochism (or Sadism & Masochism), although the initialisms S-M, SM, or S/M are also used, particularly by practitioners. Sadomasochism is not considered a clinical paraphilia unless such practices lead to clinically significant distress or impairment for a diagnosis. Similarly, sexual sadism within the context of mutual consent, generally known under the heading BDSM, is distinguished from non-consensual acts of sexual violence or aggression.