This work was designed to assess the Gly-BH impacts on the postnatal development of rat cerebellum via evaluation of locomotor activity, histological and immunohistochemical studies, and to focus on cerebellar oxidative stress-related alterations. Twenty-four new-born pups were divided into 2 equal experimental groups: the control group was kept without any treatment and Gly-BH treated group in which their mothers received (100 mg/kg b.w./day) in drinking water from 1st day of gestation to the end of pregnancy. six rats of each group were weighed deeply anesthetized and sacrificed at postnatal day-11 (PD11) and PD30 ages. For locomotor assessment, rats were tested at the PD28-30 ages. Gly-BH-treated rats suffered from decreased motor activity and showed decreased body and cerebellar weights, reduced levels of enzymatic antioxidants (SOD and CAT), and non-enzymatic antioxidant defence (GSH), and increased lipid peroxidation marker (MDA). Histopathological assessment exhibited that Gly-BH resulted in deleterious changes within cerebellar cortical layers in the form of vacuolations, decreased thickness, while Purkinje cells exhibited profound degenerative changes. In Gly-BH-treated rats, GFAP demonstrated upregulated, hypertrophied, and branched Bregman glial fibers and reactive astrogliosis. Immunolocalization of Ki-67 positive cells revealed decreased proliferation in PD11. Nevertheless, the Gly-BH-treated rats showed decreased synaptophysin immunolocalization in all cerebellar layers and on the surface of Purkinje cells. In conclusion, Gly-BH causes oxidative stress-related deleterious effects on the structure of developing cerebellar cortex and affects locomotor activity.