Deep eutectic solvents (DESs) are a class of green solvents that hold promising application in gas separation. With respect to NH3separation, reversible chemical absorption of NH3is in demand, as the contents of NH3in industrial streams are normally low, making traditional means of NH3separation inefficient. In this study, we found that N-methylacetamide (MAA) can form DESs with heterocyclic weak acids (HWAs) such as imidazole, 1,2,4-triazole, and tetrazole. The DESs were characterized by their physical properties and systematically evaluated for NH3absorption performance. The solubilities of NH3in MAA+tetrazole DESs are much higher than those in MAA+imidazole and MAA+triazole DESs, since tetrazole is more acidic than the latter two HWAs. In addition, the isotherms for NH3absorption in MAA+tetrazole DESs display nonideal profiles, suggesting the chemical behavior of NH3absorption, which is further elucidated by theoretical calculations and spectroscopic characterizations. Overall, MAA+tetrazole DESs are among the best solvents for NH3absorption, with a NH3solubility of 4.60 mol/kg at 313.2 K and 9.0 kPa. The absorption of NH3in MAA+tetrazole DESs also shows excellent selectivity for CO2and good reversibility throughout consecutive cycles, justifying the potential use of MAA+tetrazole DESs for NH3separation from industrial streams.