The wear reducing properties of aqueous solutions of ammonium thiomolybdate and ammonium thiotungstate were evaluated using a frontal cylinder-on-cylinder test tribometer on an AISI 304 steel–steel contact. The antiwear characteristics of the lubricating solutions of thiomolybdate and thiotungstate were evaluated at 24.5, 30, and 40 N keeping fixed the entrainment speed, sliding distance, temperature, and additive concentration. Although there was a reduction in wear for the two salts compared to fluid reference, it is worth mentioning that the thiotungstate additive was slightly more effective under tested lubricating contact conditions than thiomolybdate additive. Energy-dispersive X-ray spectroscopy (EDS) analysis of a wear track lubricated with thiomolybdate showed Mo and S elements and for the track lubricated with thiotungstate W and S were detected. Raman spectra of the wear track showed peaks at 373, 404 and 208, 253, 280, 353 cm−1 corresponding to 2H-MoS2 and FeS, respectively. Ammonium thiomolybdate releases sulfur atoms that also react with the freshly exposed surface, forming FeS, which takes part in reducing wear.