A review is given of the experimental investigations of the magnetocaloric effect (MCE) in rare-earth magnetic materials of different classes: heavy rare-earth metals and their alloys, iron garnets, and intermetallic compounds. The results of measurements of the MCE near phase transitions are given for the vicinity of the Curie and Neél temperatures, and also near magnetic compensation points in the case of ferromagnetism-helicoidal antiferromagnetism and helicoidal ferromagnetism–paramagnetism transitions. The contributions to the MCE made by the various magnetic sublattices in rare-earth ferromagnets are identified. Measurements of the MCE in single crystals of alloys of heavy rare-earth metals have made it possible to identify the main energy contributions to the helicoidal antiferromagnetism-ferromagnetism phase transitions and their energy dependences. The concluding section of the review deals with the technical applications of the MCE exhibited by rare-earth magnetic materials. An analysis is made of the potential applications as refrigerants in magnetic refrigerators, in thermodynamic cycles, and in structures of various types.