Glaucoma, characterized with progressive degeneration of retinal ganglion cells (RGCs), is the second frequently leading cause of sight loss in the word after cataract. Baicalin plays a protective role in age-related macular degeneration, retinopathy of prematurity, branch retinal vein occlusion, and ischemia-induced neurodegeneration in the retina. The present study aimed to investigate the role of baicalin in glaucoma. RGCs were stimulated with N-methyl-D-aspartate (NMDA) to mimic the
in vitro
model of glaucoma. A mouse model of glaucoma induced by chronic elevated intraocular pressure was also established. The apoptosis, oxidative stress, and autophagy of RGCs were detected by flow cytometry analysis, 2,7-dichlorodihydrofluorescein diacetate staining, and Western blotting, respectively. Retinal pathological changes were exhibited by hemotoxylin and eosin staining. Baicalin restrained the NMDA-induced cell apoptosis, autophagy, and oxidative stress of RGCs by activating the PI3K/AKT signaling
in vitro
. The elevated intraocular pressure-induced pathological changes in retinas of glaucoma mice were attenuated by baicalin. Moreover, the number of RGCs was significantly decreased in glaucoma mice, and then increased by baicalin treatment. Baicalin also inhibited autophagy and activated PI3K/AKT signaling
in vivo
. In conclusion, baicalin suppresses glaucoma pathogenesis by regulating the PI3K/AKT signaling
in vitro
and
in vivo
.