Herein, we demonstrate a strategy for facile synthesis of pristine MgO nanostructures at different pH values ranging from 7.9, 8.3 and 12.5 to explore their photoluminescence studies. These pH-dependent MgO nanostructures were characterized by various standard techniques such as XRD, SEM, EDS, TEM and photoluminescence (PL) spectroscopy. The obtained PL results clearly demonstrate that the PL emission spectra strongly depend upon growth environment. These nanostructures show a broad PL emission in visible region ranging from 400 to 680 nm at excitation wavelength of 330 nm. Hence, this study provides a unique feature to tailor the PL property of pristine MgO nanostructures which could be potentially used in luminescence harvesting for various optical display devices and sensing applications.