Modern wine production is unimaginable without understanding sulphur compounds. Many different forms of sulphur are found in wine, and each of them contributes uniquely to the development of flavour, aroma, colour, and ultimately the final product. The knowledge of the origin of sulphur compounds, as well as the chemical and biochemical reactions in which they participate, is crucial for oenologists, the experts in wine production, to ultimately produce high-quality wine. This work describes sulphur-containing compounds and their key properties and roles in wine. The characteristics of sulphur dioxide (SO2), the main wine preservative and additive, are explained in detail, including the sulphite forms that arise during dissociation in a reaction with water, as well as the natural production of sulphur dioxide during alcoholic fermentation. The use of sulphur dioxide is restricted to certain concentrations according to specific regulations due to its negative effects on human health, so winemakers need to know very well when and how much SO2 to add and how to determine its levels in wine. In addition to sulphur dioxide, the details of aromatic sulphur compounds are also described. These compounds play a significant role in the formation of the organoleptic characteristics of wine, which include desirable wine notes, but they can also contribute to unpleasant aromas.