The Saxberget Zn-Pb-Cu-Ag deposit is located in the western part of the Bergslagen ore district in south-central Sweden. The interpretation of the local geology is complicated due to intense hydrothermal alteration that overprinted the rocks, followed by significant deformation and metamorphism during the Svecokarelian orogeny. In this thesis, immobile-element-based lithogeochemical methods and petrographic techniques were integrated to classify the metavolcanic succession into distinct chemical units, ranging from rhyolites and dacites to basaltic andesites, and to characterize the hydrothermal alteration that overprinted the rocks. The geometric hanging wall and transitional zone of the deposit are predominantly composed of rhyolitic and dacitic rocks, with andesites being less abundant. In contrast, the geometric footwall of the deposit is primarily composed of dacitic rocks. Calc-silicate rock, approximately 1–15m thick, hosts the massive to semi-massive ore body. Two massive sulphide bodies, the A ores and B ores, which dip gently to the southeast were identified, these sulphide bodies are located at different stratigraphic levels within the transitional zone. The rocks at the geometric hanging wall and transitional zone of the deposit are overprinted by two main alteration styles: a strong–intense hydrothermal chlorite-sericite-garnet alteration recording mass gains of FeO and MgO, and mass loss of Na2O, CaO, and SiO2 and a regionally metamorphosed intense alteration of biotite±corderite+anthophyllite that envelopes the calc-silicate host rocks. The dacitic rocks in the geometric footwall are overprinted by less intense chlorite-sericite-garnet alteration recording moderate to minor MgO and SiO2 mass gain as well as minor to moderate FeO mass loss. The alteration that overprinted the rocks in the study area is asymmetric in relation to the ore zone. The alteration envelope at Saxberget suggests that the lithostratigraphy is inverted, hence, the original footwall alteration is now found in the geometric hanging wall whereas, the original hanging wall alteration constitutes the geometric footwall. Mineralisation is inferred to have formed through the neutralization of hot, acidic metalliferous fluids. Based on lithogeochemistry, rhyolitic units next to the mineralised zone with high gain of MgO and FeO as well as high mass loss of SiO2 can serve as an exploration criterion to aid future exploration in the area.