Mihai Stelescu (1907 – July 16, 1936) was a Romanian political activist.
Born in Galați, he joined, while still in high school, the Legion of the Archangel Michael (later also known as the Iron Guard), an ultra-nationalist, Fascist, and anti-Semitic political movement led by Corneliu Zelea Codreanu.
A prominent activist in his native Covurlui County, jailed more than once for his activism, he was awarded the White Cross (Crucea Albă), the movement’s highest distinction, and eventually became Codreanu’s lieutenant. In 1932, he was one of five members of the Legion to be elected to Parliament on the lists of the Corneliu Codreanu Grouping; he was also the youngest member of the Parliament at the time. Stelescu, together with Codreanu, General Gheorghe Cantacuzino-Grănicerul, Nichifor Crainic, and others, was tried for criminal conspiracy following the assassination of Prime Minister Ion G. Duca — all were acquitted by a jury comprising Legion sympathisers.
In September 1934, for mysterious reasons, Stelescu was investigated by a party jury under the leadership of Cantacuzino-Grănicerul; expelled, he is thought to have broken away from the Legion before the actual verdict. As a consequence, in 1935, he created his own political movement, originally called the White Eagles (Vulturii Albi), but later known as the Crusade of Romanianism (Cruciada Românismului), and began publishing a weekly magazine of the same name, in which he fiercely attacked Codreanu and the Legion.
There are conflicting accounts of what caused Stelescu’s dissidence. According to the Legion’s version (published much later by Codreanu's successor, Horia Sima) Stelescu was motivated by envy of Codreanu, and had even plotted to assassinate him; moreover, through his wife’s relatives, he had made contact with political operators close to King Carol II, who, as the foremost opponent of the Legion, encouraged and supported his action. Other sources have alleged that Stelescu had even been an agent of Siguranța Statului, a hypothesis relying on a statement of the writer Panait Istrati, who was a sympathiser of Cruciada Românismului; he reportedly told the writer Alexandru Talex that Stelescu was "the man of those who keep me under surveillance" (a likely reference to Romanian authorities, suspicious of Istrati's earlier communist activism).