There is a growing trend to utilize plant extracts compounds as corrosion inhibitor. Corrosion Inhibition of Mild Steel in 2M Hydrochloric acid (HCl) by leaves extract of Hibiscus rosa sinensis has been studied using weight loss measurement and spectrophotometry technique at 35oC. Characterization of Hibiscus rosa sinensis leaves extract was carried out using GC-MS technique. Results confirmed that the leaves extract of Hibiscus rosa sinensis inhibited the acid induced corrosion of Mild Steel (MS). The inhibition efficiency increases with increases in concentration of the extract. Inhibitive effect was afforded by adsorption of the extracts' components which was approximated by Freundlich adsorption isotherm, Langmuir adsorption isotherm and Temkin adsorption isotherm.