The 2D materials manifest prominent physical properties compared to their bulk counterparts due to dimensional confinement effect along one direction, which in turn allures researchers towards these materials. Many researchers have been working extensively, both theoretically and experimentally, on 2D materials. In this investigation, the 1H phase of the Na2O monolayer is computationally studied using Density Functional Theory (DFT). WIEN2K software is employed to examine the structural and electronic properties of the 1H phase of the Na2O monolayer. The 1H-Na2O monolayer crystallizes in the space group 187 with a lattice parameter, a = b = 3.54 Å and c = 15 Å. The exchange-correlation functional used for this analysis is PBE-GGA. The computational study reveals that the 1H phase of the Na2O monolayer is zero bandgap in nature. The optical properties of 1H-Na2O were investigated using the OPTIC code in WIEN2k, the peak value of the absorption coefficient was found to be 21.22 × 104 (1/cm) at 9.46 eV.