Mercury (Hg) exposure is known to damage vital components of the central nervous system primarily through oxidative stress. Although Phyllanthus amarus (PA) is reported to be rich in antioxidants, there is a dearth of relevant research evidence to show its protective activity against Mercuric chloride (HgCl2)-induced neurotoxicity. Accordingly, this study was designed to investigate the possible protective activity of aqueous Phyllanthus amarus leaf extract (APALE) in HgCl2-exposed rats using standard neurobehavioral assessments. Thirty adult Wistar rats were randomized into six groups of five rats each viz: A: Control, distilled water; B: HgCl2 (4 mg/kg body wt.); C: APALE (200 mg/kg body wt.) + HgCl2 (4 mg/kg); D: APALE (400 mg/kg body wt.) + HgCl2 (4 mg/kg); E: APALE (200 mg/kg body wt.); F: APALE (400 mg/kg body wt.). All administrations were through an orogastric tube for 14 days. Thereafter, neurobehavioral tests (open field, novel object and Y-maze) were done and experimental rats were sacrificed by cervical dislocation. Body, brain and cerebellar weights were examined across all groups. HgCl2 exposure significantly (p<0.0.05) decreased whole body weight across experimental groups. Similarly, a reduction in brain and cerebellar weight was observed. Significant neurobehavioral alterations to locomotion, discrimination index and cognition/memory, induced by HgCl2, were observed across experimental groups. However, protection against the deleterious effects induced by HgCl2 was observed following pretreatment with APALE. Conclusively, these findings show that APALE demonstrated potent protective activity against HgCl2-induced neurotoxicity and may be useful in the management of Hg toxicity and other related disorders.