Herein, A study of corrosion inhibition of mild steel (MS) in 1.0 M HCl by Tetraclinis articulata extract as a green inhibitor had been achieved via chemical and electrochemical methods. Open circuit potential (OCP), Potentiodynamic polarization, electrochemical impedance spectroscopy and electrochemical frequency modulation tests had been examined. Adsorption & thermodynamic activation parameters had been recorded and evaluated. Temperature effect on the mild steel corrosion inhibition in a range between 298-328 K had been evaluated. The mild steel samples surface morphology in existence and nonexistence of Tetraclinis articulata extract had been evaluated via FT-IR spectroscopy measurements, Scanning Electron Microscopy and Atomic Force Microscopy. The gained data confirmed the protective layer formed on mild steel surface and demonstrated that the compounds which had been found in Tetraclinis articulata extract act as an effective and good inhibitors. Tafel curves demonstrated that the tested compound proceeds as a mixed-type inhibitor. The adsorption mode of Tetraclinis articulata extract had been matched with the Temkin adsorption isotherm model. The inhibition efficiency (IE%) had been found to improve with improvement of Tetraclinis articulata extract doses achieving maximum inhibition efficiency more than 80% at 298K.