The growing demand for compact, high-performance wireless communication systems has driven the need for advanced antenna materials capable of overcoming limitations in size, bandwidth, and efficiency. Nanoferrites, owing to their unique magneto-dielectric properties at the nanoscale, offer enhanced permeability, tunable permittivity, reduced losses, and improved high-frequency behaviour, making them highly suitable for antenna miniaturization and performance optimization. This chapter provides a comprehensive overview of nanoferrites, focusing on their fundamental structural, magnetic, and dielectric properties—such as spinel structure, size-dependent behaviour, complex permeability and permittivity, and cation distribution—and their influence on electromagnetic wave propagation and antenna characteristics. It further examines the critical role of synthesis techniques, including solid-state, sol–gel, co-precipitation, hydrothermal, and combustion methods, in controlling particle size, morphology, crystallinity, and overall electromagnetic performance. The chapter also discusses post-synthesis processing approaches and practical integration of nanoferrites into antenna designs for bandwidth enhancement, size reduction, frequency tunability, and EMI suppression. Finally, key challenges such as magnetic losses, particle agglomeration, thermal stability, and scalability are highlighted, establishing a clear structure–property–performance relationship essential for the development of efficient nanoferrite-based antenna systems.