[en] In this study, zeta potentials of graphitic carbon nitride (g-C₃N₄) nanoparticles were detailedly investigated under various electrolytes, solution pH, and humic acid (HA) concentration conditions. The hydrodynamic radius of g-C₃N₄ nanoparticles was measured to be 388.9 ± 24 nm, and the specific surface area of the g-C₃N₄ nanoparticles was measured to be 46.2 m² g⁻¹. The absolute values of g-C₃N₄ zeta potentials significantly decreased with the increasing ionic strength (IS) due to the charge screening. Compared to the monovalent cation, the zeta potentials of g-C₃N₄ were less negative with the presence of divalent cations. In addition, K⁺ was more effective than Na⁺ in decreasing the absolute values of g-C₃N₄ zeta potentials, and Ca²⁺ was more effective than Mg²⁺ in decreasing the absolute values of g-C₃N₄ zeta potentials. When NaCl and CaCl₂ were used as the electrolytes, the zeta potentials of g-C₃N₄ became less negative with the decreasing pH conditions. When FeCl₃ and AlCl₃ were used as the electrolytes, the zeta potentials of g-C₃N₄ became more positive with increasing solution pH due to the changing species of Fe³⁺ and Al³⁺. The zeta potentials of g-C₃N₄ were significantly more negative with the presence of HA. The results from this work indicated electrolytes, solution pH, and HA concentration conditions play a complex role in zeta potentials of g-C₃N₄ nanoparticles in aqueous environment.