Abstract: Sensorineural hearing loss (SNHL) represents a major global public health issue, profoundly affecting patients' physical and psychological well-being as well as their quality of life. Therapeutic options for SNHL remain limited due to irreversible damage to cochlear hair cells, degeneration of spiral ganglion neurons, and the restrictive nature of the blood–labyrinth barrier (BLB). The rapid advancement of nanotechnology in biomedical fields, characterized by its tunable particle size, active targeting capability, and multifunctionality, has demonstrated promising potential to overcome the BLB and achieve precise diagnosis and targeted therapy of inner ear disorders. As a result, nanotechnology has emerged as a research hotspot in the field of hearing loss treatment, offering a novel strategy for precision medicine. This review systematically summarizes the core applications and recent progress of nanotechnology in the treatment of SNHL, including three major directions: nanocarrier-mediated drug delivery, protection and regeneration of cochlear hair cells, and bionic nano-based auditory devices. Additionally, current challenges and future development trends of these technologies are discussed. This review aims to provide a theoretical basis for the application of nanotechnology in the diagnosis and treatment of SNHL and to offer insights for its clinical translation.