Abstract: Mid-infrared lasers operating in the 3 μm spectral region exhibit significant potential across a diverse range of fields. These include defense applications such as infrared countermeasures and remote sensing, biomedical uses like tissue ablation and gas spectroscopy, precise molecular detection for environmental monitoring, and advanced industrial material processing. Currently, laser outputs in this band are primarily achieved through solid-state lasers, optical parametric oscillators, gas lasers, and rare-earth-doped fluoride fiber lasers. Among these technological routes, rare-earth-doped fluoride fiber lasers are increasingly regarded as one of the most promising approaches for generating high-quality 3 μm radiation. This preference stems from their intrinsic advantages, including superior beam quality, compact and robust all-fiber architecture, high environmental stability, and efficient heat dissipation capabilities. Accordingly, this paper provides a systematic review of the recent and rapid research progress in high-power continuous-wave and pulsed lasers at the 3 μm band based on erbium-doped fluoride fibers. It summarizes the current state of the art in the development of key components for mid-infrared fiber lasers, such as fiber end caps, fiber gratings, and pump combiners. Furthermore, the review discusses the prevailing technical challenges, ongoing research directions, and future development trends, offering a comprehensive reference for further advancements in this dynamically evolving and technologically critical field.