Michael Servetus (; Spanish: Miguel Serveto as real name; French: Michel Servet; also known as Miguel Servet, Miguel de Villanueva, Revés, or Michel de Villeneuve; 29 September 1509 or 1511 – 27 October 1553) was a Spanish theologian, physician, cartographer, and Renaissance humanist. He was the first European to correctly describe the function of pulmonary circulation, as discussed in Christianismi Restitutio (1553). He was a polymath versed in many sciences: mathematics, astronomy and meteorology, geography, human anatomy, medicine and pharmacology, as well as jurisprudence, translation, poetry, and the scholarly study of the Bible in its original languages.

He is renowned in the history of several of these fields, particularly medicine. He participated in the Protestant Reformation, and later rejected the Trinity doctrine and mainstream Catholic Christology. After being condemned by Catholic authorities in France, he fled to Calvinist Geneva where he was denounced by Calvin and burned at the stake for heresy by order of the city's governing council.