Multi-sulphur isotope (32S, 33S, 34S, and 36S) analysis of galena, sphalerite, and pyrite from 30 Archean volcanogenic massive sulphide deposits and occurrences from across the Slave Province reveals a variable contribution from Archean atmosphere-derived sulphur. Mass-independent fractionation of the sulphur isotopes produced anomalous abundances (Δ33S) of the sulphur isotopes that were incorporated to varying degrees in deposits that formed in different tectonic settings. Our data indicate that deposits of the bimodal-mafic type (bimodal rift setting) are characterized by a restricted range of Δ33S from -0.3 to 0.1 per mil, whereas deposits of the bimodal-felsic type (arc-like settings) exhibit a broader range in Δ33S, from -0.8 to 0.6 per mil. Mantle-derived (juvenile) sulphur is essentially the sole source of sulphur in deposits of the bimodalmafic type, whether derived directly by magmatic degassing, or indirectly by leaching of magmatic sulphides in the associated hydrothermal system; these deposits are also characterized by relatively low silver contents. Bimodal-felsic type deposits, typified by high silver contents, contain variable amounts of atmosphere-derived sulphur that was more readily available in arc-like settings.