Sulfur-bearing species play critical roles in atmospheric physical-chemical processes, atmosphere-surface interactions, and the geological evolution of Venus. Most data on atmospheric sulfur have been obtained through telescopic and spacecraft spectroscopic investigations, along with limited in situ measurements using entry probes. The atmospheric composition below ≈20 km is poorly understood and estimated by extrapolating measured contents toward the surface and using thermochemical and mixing models. The bulk sulfur content was measured in solid surface samples collected from three landing sites, while the geochemistry of sulfur in the interior remains poorly constrained. Sulfur dioxide is the most abundant sulfur-bearing gas in the middle and lower atmosphere. Photochemical dissociation of CO2 above the clouds into CO and atomic oxygen, along with the subsequent oxidation of SO2 to H2SO4, sustains thick global clouds rich in sulfuric acid. Interaction of SO2 with basaltic glasses and Ca-bearing minerals leads to the formation of sulfates, consistent with the elevated sulfur content in surface probes. Carbonyl sulfide, OCS, is the most abundant reduced atmospheric gas. It forms in the lower atmosphere from CO and sulfur gases and is oxidized by SO3, which forms via pyrolysis of H2SO4 gas below the clouds. OCS can be formed and consumed by altering and forming sulfide minerals. In Hadley cell-type atmospheric circulation, low-latitude upwelling delivers OCS to the clouds, while high-altitude downwelling brings OCS-depleted and CO-enriched gas to the deep atmosphere. The occurrence and fate of S1–8 gases and condensates (S8) must be more constrained. Some models suggest the formation of Sn gases below the clouds, while others imply that they are formed via photochemical reactions in the upper clouds. S2 is consumed through OCS production in the deep atmosphere and released via sulfatization of silicates. Chemical disequilibria drive reactions in the atmosphere, but some gases may reach equilibrium at the surface. Fe sulfide-oxide and/or sulfate-silicate phase equilibria in a permeable surface layer could control the abundance and speciation of sulfur-bearing gases in the deep atmosphere. Pyritization and sulfatization of surface materials through gas-solid reactions are thermodynamically more favorable in the highlands but require confirmation. Past volcanic degassing mainly constituted the current inventory of atmospheric sulfur. Although cometary dust is a minor net source of atmospheric sulfur, it may account for the elevated mixing ratios of sulfur-bearing gases in the upper mesosphere. Cosmic sources could account for possible metal sulfates in the clouds. Aside from sequestered atmospheric sulfur, the chemical composition and radar-based morphology of immense volcanic formations suggest an abundance of sulfur and sulfide mineralogy (pyrrhotite, pentlandite) typical of tholeiitic and alkaline basalts. The morphology and thermal emissivity of highly tectonically deformed tessera terrain do not rule out the possibility of exposure to rocks formed in H2O-rich exogenic and/or endogenic environments. The presence of sulfates in those rocks depends on the H2O history, which may or may not involve oxidizing aqueous and/or magmatic environments. Hydrogen escaping from early Venus with a putative water ocean could have led to sulfate-rich seawater and subsequent sulfate-rich rock formations. In contrast to Earth’s marine sediments, abundant pyrite may not have precipitated in Venus’ counterparts due to the absence of biological sulfate reduction and sufficient organic matter. The formation of a Fe sulfide-oxide assemblage in surface materials could result from the coupled physical-chemical evolution of the atmosphere-surface system following global volcanic resurfacing. It is essential to prioritize the examination of sulfur-bearing species and isotopes in future remote and in situ studies of atmospheric gases, aerosols, and both chemically altered and pristine rocks. The upcoming Venus Orbital Mission, DAVINCI, VERITAS, and EnVision missions will explore atmospheric and surface compositions, leading to a better understanding of the behavior of sulfur on Earth’s sister planet.