Illarion Mikhailovich Pryanishnikov (Russian: Илларио́н Миха́йлович Пря́нишников; 20 March [O.S. 1 April] 1840 – 12 March [O.S. 24 March] 1894) was a Russian painter, one of the founders of the Peredvizhniki artistic cooperative.

Illarion Pryanishnikov was born in the village of Timashovo (today's Kaluga Oblast) in a family of merchants. From 1856 to 1866 he studied in the Moscow School of Painting, Sculpture and Architecture in the classes of Evgraf Sorokin and Sergey Zaryanko.

His picture Jokers. Gostiny Dvor in Moscow, painted during his last year in the School, brought him immediately a wide reputation. In this small canvas he provides an original depiction of the humiliation of human dignity, callousness and cruelty in the world, where everything is bought and sold. After painting the tipsy merchants, who with a jeer are compelled to dance under the concertina and a poor elderly official, the artist created a whole series of pictures on the themes of moral deformity and complacent caddishness. The paintings caused the indignation of some adherents of academic art who felt that the young painter became the destroyer of the "high" destination of art meant to express the ideals of the eternal truths.

In 1870 Pryanishnikov received the title of the "painter of 1st degree". From 1873 until his death he was a teacher in the MSoPSA and his apprentices were Konstantin Korovin, Vitold Byalynitsky - Birulya, Mikhail Nesterov and others.

From the outset of the existence of the union of Peredvizhniks, he was a member, and from the second exhibition he was one of directors of the union. Although Pryanishnikov lived mainly in Moscow, he often visited the Russian North where he sketched. He took part in the decoration of the Cathedral of Christ the Saviour.

Pryanishnikov died in Moscow where one of the streets was named after him.