Fedoseevtsy, also Fedoseyans (Федосеевцы, феодосиевцы in Russian) was an oppositionary religious movement in Imperial Russia and one of the denominations among the Bespopovtsy.
The Fedoseevtsy movement was born amidst the Old Believers (mostly peasants and posad people) in Northwest Russia. It was founded by an ex-deacon Feodosiy Vasiliyev (1661-1711). The Fedoseevtsy were displeased with a certain group within the Bespopovtsy, namely Pomortsy, who had been diverging from the strict principles of the Old Believers and adopted a custom of praying for the tsar (моление за царя). Initially, the Fedoseevtsy were irreconcilable towards the serfdom in Russia and observed strict asceticism, negating the institution of marriage. In the late 18th century, the Fedoseevtsy centered around a group led by Ilya Kovylin (1731-1809) with their all-Russian "headquarters" at the Preobrazhenskoye cemetery in Moscow. With the development of social inequality among the Fedoseevtsy, their doctrine gradually began to lose its elements of social protest. In 1848, they adopted the custom of praying for the Tsar. In the second half of the 19th century, a group of the so-called "newlyweds" (новожёны) detached itself from the Fedoseevtsy movement, acknowledging the institution of marriage.
There were small groups of the Fedoseevtsy in the Soviet Union, who had been moving away from religious intolerance and asceticism.