AbstractIntroductionOptic nerve injury is a leading cause of irreversible blindness worldwide. The retinal ganglion cells (RGCs) and their axons cannot be regenerated once damaged. Therefore, reducing RGC damage is crucial to prevent blindness. Accordingly, we aimed to investigate the potential influence of the gut microbiota on RGC survival, as well as the associated action mechanisms.MethodsWe evaluated the effects of microbiota, specificallyBifidobacterium, on RGC. Optic nerve crush (ONC) was used as a model of optic nerve injury. Vancomycin andBifidobacteriumwere orally administered to specific pathogen‐free (SPF) mice.ResultsBifidobacteriumpromoted RGC survival and optic nerve regeneration. The administration ofBifidobacteriuminhibited microglia activation but promoted Müller cell activation, which was accompanied by the downregulation of inflammatory cytokines and upregulation of neurotrophic factors and retinal ERK/Fos signaling pathway activation.ConclusionsOur study demonstrates thatBifidobacterium‐induced changes in intestinal flora promote RGC survival. The protective effect ofBifidobacteriumon RGC can be attributed to the inhibition of microglia activation and promotion of Müller cell activation and the secondary regulation of inflammatory and neurotrophic factors.