Orgone (/ˈɔːrɡoʊn/ OR-gohn) is a pseudoscientific concept variously described as an esoteric energy or hypothetical universal life force. Originally proposed in the 1930s by Wilhelm Reich, and developed by Reich's student Charles Kelley after Reich's death in 1957, orgone was conceived as the anti-entropic principle of the universe, a creative substratum in all of nature comparable to Mesmer's animal magnetism (1779), to the Odic force (1845) of Carl Reichenbach and to Henri Bergson's élan vital (1907). Orgone was seen as a massless, omnipresent substance, similar to luminiferous aether, but more closely associated with living energy than with inert matter. It could allegedly coalesce to create organization on all scales, from the smallest microscopic units—called "bions" in orgone theory—to macroscopic structures like organisms, clouds, or even galaxies.

Reich argued that deficits or constrictions in bodily orgone were at the root of many diseases, most prominently cancer, much as deficits or constrictions in the libido could produce neuroses in Freudian theory. Reich founded the Orgone Institute ca. 1942 to pursue research into orgone energy after he immigrated to the US in 1939; he used it to publish literature and distribute material relating to the topic for over a decade. Reich designed special "orgone energy accumulators"—devices ostensibly collecting orgone energy from the environment—to enable the study of orgone energy and to be applied medically to improve general health and vitality. Ultimately, the U.S. Food and Drug Administration (FDA) obtained a federal injunction barring the interstate distribution of orgone-related materials because Reich and his associates were making false and misleading claims. But an associate of Reich violated the injunction, and a judge later sentenced Reich to jail and ordered the banning and destruction of all orgone-related materials at the institute.

Reich denied the assertion that orgone accumulators could improve sexual health by providing orgastic potency.

The National Center for Complementary and Integrative Health lists orgone as a type of "putative energy", writing that "putative energy fields (also called biofields) have defied measurement to date by reproducible methods. Therapies involving putative energy fields are based on the concept that human beings are infused with a subtle form of energy. This proposed vital energy or life force is known under different names in different cultures, such as qi ... prana, etheric energy, fohat, orgone, odic force, mana, and homeopathic resonance".

After Reich's death, research into the concept of orgone passed to some of his students, such as Kelley, and later to a new generation of researchers. An Institute for Orgonomic Science was founded in New York in 1982, dedicated to the continuation of Reich's work; it publishes a digital journal and collects corresponding works. However, there was no empirical support for the concept of orgone in medicine or the physical sciences, and research into the concept concluded with the end of the institute.

Nevertheless, Stefan Muschenich, a psychiatrist in Germany keen to discover an empirical basis for the orgone hypothesis, did publish some positive results in the 1980s and 90s.

The concept of orgone belongs to Reich's later work after he immigrated to the US. Reich's early work was based on the Freudian concept of the libido, though influenced by sociological understandings with which Freud disagreed but which were to some degree followed by other prominent theorists such as Herbert Marcuse and Carl Jung. While Freud had focused on a solipsistic conception of mind in which unconscious and inherently selfish primal drives (primarily the sexual drive, or libido) were suppressed or sublimated by internal representations (cathexes) of parental figures (the superego), for Reich libido was a life-affirming force repressed by society directly. For example, in one of his better-known analyses, Reich observes a workers' political rally, noting that participants were careful not to violate signs that prohibited walking on the grass; Reich saw this as the state co-opting unconscious responses to parental authority as a means of controlling behavior. He was expelled from the Institute of Psycho-analysis because of these disagreements over the nature of the libido and his increasingly political stance. He was forced to leave Germany soon after Hitler came to power.

Reich took an increasingly bioenergetic view of libido, perhaps influenced by his tutor Paul Kammerer and another biologist, Otto Heinrich Warburg. In the early 20th century, when molecular biology was in its infancy, developmental biology in particular still presented mysteries that made the idea of a specific life energy respectable, as was articulated by theorists such as Hans Driesch. As a psycho-analyst, Reich aligned such theories with the Freudian libido, while as a materialist, he believed such a life force must be susceptible to physical experiments.