Ferrites are ceramic magnetic materials primarily made of iron oxide along with various metal ions, demonstrating remarkable electrical resistivity, chemical stability, and advantageous magnetic properties. As the particle size is reduced to the nanoscale, ferrites reveal unique magnetic, dielectric, and electrical characteristics due to surface effects, quantum confinement, and size-related phenomena. Thus, nanoferrites provide adjustable magnetic permeability and dielectric permittivity, making them particularly advantageous for sophisticated electromagnetic and antenna applications. This chapter discusses the structural features of spinel, garnet, and hexaferrite systems, focusing on cation distribution and its impact on magnetic characteristics. A comparison of different synthesis methods, such as sol–gel, co-precipitation, hydrothermal, combustion, and microemulsion techniques, is presented regarding their effectiveness in controlling morphology and crystallinity. Additionally, the chapter explores the dielectric properties, conduction mechanisms, and the significant role of nanoferrites in antenna miniaturization, impedance matching, bandwidth enhancement, and tunability. The potential of nanoferrites in the advancement of intelligent, reconfigurable, and high-frequency antenna systems is also emphasized.