The Iron Guard (Romanian: Garda de fier pronounced [ˈɡarda de ˈfjer]) is the name most commonly given to a far-right movement and political party in Romania in the period from 1927 into the early part of World War II. The Iron Guard was ultra-nationalist, fascist, anti-communist, and promoted the Orthodox Christian faith. It is also considered an antisemitic organization, an ideology even going so far as to demand the introduction of "state anti-semitism". Romanian antisemitism had deep roots in the teachings of the Romanian Orthodox Church. Even as the Iron Guard moved beyond traditional religious antisemitism to promote economic and racial antisemitism, and violence against Jews, they did not abandon religious belief and religious language and symbolism was used in the speeches, poetry and songs of the Iron Guard. The youth movement had its stronghold in the Faculty of Theology of the University of Bucharest.

Originally founded by Corneliu Zelea Codreanu on July 24, 1927, as the Legion of the Archangel Michael ("Legiunea Arhanghelului Mihail"), and led by him until his assassination in 1938, adherents to the movement continued to be widely referred to as "legionnaires" (sometimes "legionaries"; Romanian: legionarii) and led to the organization of the "Legion" or the "Legionary Movement" ("Mişcarea Legionară"), despite various changes of the (intermittently banned) organization's name. In March 1930 Codreanu formed the "Iron Guard" ("Garda de Fier") as a paramilitary political branch of the Legion; this name eventually came to refer to the Legion itself. Later, in June 1935, the Legion changed its official name to the "Totul pentru Ţară" party, literally "Everything for the Country", but commonly translated as "Everything for the Fatherland" or occasionally "Everything for the Motherland".

Corneliu Zelea Codreanu (Romanian pronunciation: [korˈnelju ˈzele̯a koˈdre̯anu]; September 13, 1899 – November 30, 1938) — born Corneliu Zelinski and commonly known as Corneliu Codreanu — was a Romanian politician of the far right, the founder and charismatic leader of the Iron Guard or The Legion of the Archangel Michael (also known as the Legionary Movement), an ultra-nationalist and violently antisemitic organization active throughout most of the interwar period. Generally seen as the main variety of local fascism, and noted for its mystical and Romanian Orthodox-inspired revolutionary message, it grew into an important actor on the Romanian political stage, coming into conflict with the political establishment and the democratic forces, and often resorting to terrorism. The Legionaries traditionally referred to Codreanu as Căpitanul ("The Captain"), and he held absolute authority over the organization until his death.

Codreanu, who began his career in the wake of World War I as an anticommunist and antisemitic agitator associated with A. C. Cuza and Constantin Pancu, was a co-founder of the National-Christian Defense League and assassin of the Iaşi Police prefect Constantin Manciu. Codreanu left Cuza to found a succession of movements on the far right, rallying around him a growing segment of the country's intelligentsia and peasant population, and inciting pogroms in various parts of Greater Romania. Several times outlawed by successive Romanian cabinets, his Legion assumed different names and survived in the underground, during which time Codreanu formally delegated leadership to Gheorghe Cantacuzino-Grănicerul. Following Codreanu's instructions, the Legion carried out assassinations of politicians it viewed as corrupt, including Premier Ion G. Duca and its former associate Mihai Stelescu. In parallel, Corneliu Zelea Codreanu advocated Romania's adherence to a military and political alliance formed around Nazi Germany.