The Strigolniki (singular Strigólnik–Стригольник in Russian) were followers of the first Russian heretical sect of the middle of the 14th and first half of the 15th century, established in Pskov and later in Novgorod and Tver.

The origins of the name are unknown. Some historians believe it has something to do with handicrafts that the first Strigolniki were engaged in, such as cloth-cutting or hairdressing (it appears that the word strigolnik derives from the modern Russian verbs strich' or podstrigat', which means "to cut"). Others think the name comes from a special initiation ceremony (a specific haircut, or strizhka), performed by a deacon named Karp – a supposed founder of the sect (together with deacon Nikita).

Active participants of the sect were tradespeople and low-ranking clergy. They renounced all ecclesiastic hierarchy and monasticism, sacraments of priesthood, communion, repentance, and baptism, which had been accompanied by large fees ("extortions", in their view) in favor of the clergy. Criticizing and exposing the venality, vices, and ignorance of the priests, the Strigolniki demanded the right to a religious sermon for laymen. Their sermons were full of social motifs: they reproached the rich for enslaving the free and the poor.

Deacon Karp found many followers in Pskov, but had to move to Novgorod to avoid persecution. Fearing that the Strigolniki would challenge its authority, the Russian Orthodox Church dealt with them in a harsh manner. In 1376, instigated citizens of Novgorod apprehended most members of the sect and drowned them in the Volkhov River. Beginning in 1382, the sect was opposed by Archbishop Dionysios.

However, the teachings of the Strigolniki lived on. They were widely spread in Novgorod, Pskov, and also in Tver, where bishops Feodor Dobry and Yevfimiy Vislen came forward with their support for the movement. In the early 1400s, the Strigolniki teachings were denounced by Photios, Metropolitan of Kiev and all Russia.

There has been no news of the sect since the second half of the 15th century. Some historians believe that it merged with the Sect of Skhariya the Jew. The Orthodox Church believes the heresy was ended in 1427.