A thiol is the sulfur analogue of an alcohol, containing an –SH group in place of the –OH group, written R–SH. Because sulfur is larger and less electronegative than oxygen, thiols are more acidic and far more strongly smelling than the corresponding alcohols, and are responsible for many characteristic odours. They are named with the suffix '-thiol'; the –SH group contrasts directly with the alcohol's hydroxyl (–OH) group.

硫醇是醇的硫类似物,以 –SH 基团代替 –OH 基团,写作 R–SH。由于硫比氧原子更大、电负性更低,硫醇比相应的醇更具酸性、气味也强烈得多,是许多特征气味的来源。它们以词尾“-thiol(硫醇)”命名;–SH 基团与醇的羟基(–OH)形成直接对照。