稀土磁铁是指由稀土元素合金所组成的强力永久磁铁，在1970至1980年代开始相关研究。在永久磁铁中，稀土磁铁所能产生的磁场最大，比铝镍钴合金磁铁或铁氧体磁铁的磁场都大很多。稀土磁铁一般可以产生超过1.4特斯拉的磁场，而铁氧体磁铁或陶瓷磁铁大约只有0.5至1个特斯拉。稀土磁铁中最常见的有以下二种：钕磁铁（也称做钕铁硼磁铁）及钐钴磁铁，二种磁铁分别含有稀土元素中的钕及钐。稀土磁铁的材质非常脆，而且容易受到腐蚀，因此一般会在外层镀其他金属保护稀土磁铁本身。

稀土磁铁的稀土一词常造成误解，其实稀土元素不是罕见稀有的元素，在地壳上的丰度大约和锡和铅相当。稀土磁铁的研究约从1966年开始，美国空军材料实验室的科学家K. J. Strnat和G. Hoffer发现了钇和钴的合金YCo₅，其磁向各异性常数较任何已知材料的数据都要高。

Rare-earth magnets are strong permanent magnets made from alloys of rare earth elements. Developed in the 1970s and '80s, rare-earth magnets are the strongest type of permanent magnets made, producing significantly stronger magnetic fields than other types such as ferrite or alnico magnets. The magnetic field typically produced by rare-earth magnets can exceed 1.4 teslas, whereas ferrite or ceramic magnets typically exhibit fields of 0.5 to 1 tesla. There are two types: neodymium magnets and samarium-cobalt magnets. Magnetostrictive rare-earth magnets such as Terfenol-D also have applications-- e.g. in speakers. Rare earth magnets are extremely brittle and also vulnerable to corrosion, so they are usually plated or coated to protect them from breaking, chipping, or crumbling into powder.