Corrosion of metals is a serious environmental problem and has been given much attention in the oil and gas industries. In several industrial processes (acid cleaning and etching, removal of rust and scale), metal surfaces are often made to come in contact with acids. In the present study, an attempt was made to examine Poupartia birrea (P. birres) back extract as a potential green corrosion inhibitor for mild steel in a 0.5 M H2SO4 medium, using the weight loss determination method. The results of our work indicate that highest inhibition efficiency exhibited by Poupartia birrea is 70%. The inhibiting effect of the studied extract could be attributed to the presence of phytochemical constituents present in the extract that are adsorbed on the surface of the mild steel. The plant extract can, hence, be considered as being eco-friendly and an effective green corrosion inhibitor for mild steel exposed to an acid medium.