This review discusses different techniques for green synthesis of magnetic spinel nanoparticles (magnetite, cobalt ferrite, nickel ferrite, cupper ferrite, and their composites). The green methods lead to the formation of nanoparticles with less toxicity, high sustainability, and improved physicochemical properties. The aim of green chemistry is to involve the nontoxic capping and reducing agents, obtained from nature (extracts of plant leaves, plant roots, fruits, seeds, etc.) for nanoparticle synthesis process. “Green” spinel nanoparticles can be formed at certain temperatures and pH in order to obtain the desired morphology and particle size, thereby offering potential and promising applications in biomedical, magnetic hyperthermia, biocatalysis, drug delivery systems, etc. © 2019, Springer Nature Switzerland AG.