A Rare Earth SmCo magnets, a type of rare-earth magnet, is a strong permanent magnet made of an alloy of samarium and cobalt. They were developed in the early 1960s based on work done by Karl Strnat and Alden Ray at Wright-Patterson Air Force Base and the University of Dayton, respectively. In particular, Strnat and Ray developed the first formulation of SmCo₅.

They are generally ranked similarly in strength to neodymium magnets but have higher temperature ratings and higher coercivity. They are brittle and prone to cracking and chipping. Samarium–cobalt magnets have maximum energy products (BH_max) that range from 16 megagauss-oersteds (MG·Oe) to 33 MG·Oe, that is approx. 128 kJ/m³ to 264 kJ/m³; their theoretical limit is 34 MG·Oe, about 272 kJ/m³. They are available in two “series”, namely Series 1:5 and Series 2:17.

Because of the characteristics of Rare Earth SmCo Magnets are most commonly used in applications that require high operating temperatures such as generators, pump couplings, sensors, motors, marine applications, and in the automotive, aerospace, military and food and manufacturing industries.