Structural and electronic properties of Li 3 GaP 2 and Li 3 GaN 2 have been investigated by the first-principles calculations within the density functional theory. The calculated lattice parameters of the two compounds are in excellent agreement with the available experimental data. Both Li 3 GaP 2 and Li 3 GaN 2 are direct band gap semiconductors with the band gaps of 1.26eV and 2.37eV, respectively. The Ga–P (Ga–N) and Li–P bonds consist of a mixture of ionic character and covalent nature, while the Li–N bond exhibits almost ionic. The bonds in the Li 3 GaP 2 are shown to have stronger covalency and weaker ionicity as compared to the corresponding ones in the Li 3 GaN 2 .