Boris Pavlovich Belousov (; 19 February 1893 – 12 June 1970) was a Soviet chemist and biophysicist who discovered the Belousov–Zhabotinsky reaction (BZ reaction) in the early 1950s. His work initiated the field of modern nonlinear chemical dynamics.
The Belousov family had strong anti-Tsarist sympathies and, after the Russian Revolution of 1905, they were arrested and later forced to leave the country. They settled in Switzerland, where Boris studied chemistry in Zürich.
Returning to Russia at the beginning of World War I, Belousov tried to join the army, but was denied for health reasons. He took up a job in a military lab under the direction of the chemist Vladimir Ipatiev. as "impossible". He took this very hard.
The biochemist Simon El'evich Shnoll, at the Institute for Theoretical and Experimental Biophysics in Pushchino, heard of Belousov's work and tried to encourage him to continue. Belousov gave Shnoll some of his experimental notes and agreed to publish an article in a rather obscure, non-reviewed, journal, but then essentially quit science. Shnoll gave the project to a graduate student, Anatol Zhabotinsky, who investigated the reaction in detail and succeeded in publishing his results. The reaction now bears the names of both Belousov and Zhabotinsky.
Belousov was posthumously awarded the Lenin Prize in 1980 for his work on the BZ reaction.