The need for small, broadband, effective, and multipurpose antennas is growing due to the quick development of contemporary wireless communication systems. In this regard, dielectric, magnetic, and magneto-dielectric materials have become essential facilitators for performance adjustment, bandwidth enhancement, and antenna shrinking. Reliable antenna design and simulation depend on accurate characterisation of these materials over pertinent frequency ranges. This chapter provides a thorough and organized summary of dielectric and magnetic characterisation methods designed especially for antenna applications. After discussing the basic dielectric and magnetic characteristics that affect antenna performance, low-frequency, resonant, and microwave characterisation techniques are thoroughly described. From an antenna engineering standpoint, the significance, benefits, and drawbacks of vector network analyzer-based techniques, transmission-line methods, resonant cavity perturbation, and free-space characterisation methodologies are highlighted. The chapter also discusses practical issues in obtaining material properties for realistic antenna settings, loss causes, calibration difficulties, and frequency dispersion. This chapter is a useful resource for researchers and engineers working on advanced antenna substrates, magneto-dielectric materials, and next-generation RF and microwave antenna systems because it connects material characterization techniques with antenna performance requirements.