The 3?5 μm mid-infrared band situated within the atmospheric transmission window and encompassing numerous absorption bands of gas molecules, has drawn extensive concern in the fields such as laser communication, biomedical, material processing, military confrontation, and aerospace. Among diverse types of lasers, fiber lasers stand out for their portability and stability, thus serving as an excellent laser light source. Mid-infrared fiber materials, such as fluoride glass, have the advantages of low phonon energy, high transmittance, high solubility of rare earth ions, and a wide transmission window, which can be used as gain materials for mid-infrared lasers. Fluoride glasses are classified into fluorozirconate, fluoroaluminate, and fluoroindate glasses. Mid-infrared glass fibers have achieved 4.3 μm fluorescence output, representing the longest wavelength mid-infrared fluorescence output obtained in fluoride fibers to date. This study reviews the current research and development of fluoride glass composition and glass structure, and focuses on introducing the fluoroaluminate, fluorozirconate, and fluoroindate glasses and fibers developed by our team, which have good stability and high laser damage threshold. It also reports the progress in mid-infrared laser output achieved by our team.