Hydrogen bonding in S–H⋯N systems has received little attention compared to other hydrogen bond motifs. To characterise S–H⋯N bonding, infrared spectra of the most fundamental S–H⋯N system—the H2S·NH3 complex—were recorded in solid argon. These experiments were complemented by high level ab initio and density functional theory calculations. The H2S symmetric stretch was observed to shift by -155.3 cm-1 when mixed with NH3, while the NH3 umbrella mode was found to shift by +31.8 cm-1. These, as well deuterium and isotopologue studies indicated the formation of a complex. The structure of the H2S·NH3 complex was determined to be almost identical to that of the H2O·NH3 complex, with a nearly linear S–H⋯N bond. A binding energy of 8.6 kJ mol-1 (720 cm-1) was calculated at the CCSD(T) level of theory extrapolated to the complete basis set limit. Anharmonic frequency calculations at the DSD-PBEP86-D3BJ/aug-cc-pV(D+d)Z level of theory produced frequencies with a RMSD of 13 cm-1 for the complex, relative to the experimental values. Comparison with previous work showed that the S–H⋯N bond is weaker in H2S·NH3 than the O–H⋯N bond in the H2O·NH3 system.