Orgone () 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. A judge later ruled to jail Reich and ordered the banning and destruction of all orgone-related materials at the institute after an associate of Reich violated the injunction. 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". 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 scientists in Germany keen to discover an empirical basis for the orgone hypothesis (the first positive results of which were provided in 1989 by Stefan Muschenich). There is 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. Founded in 1982, the Institute for Orgonomic Science in New York is dedicated to the continuation of Reich's work; it both publishes a digital journal on it and collects corresponding works.