糖醇（Sugar alcohol）是指糖类的醛、酮羰基被还原为羟基后生成的多元醇，通式 H(CHOH)_n+1H。

实验室一般通过用硼氢化钠、钠汞齐或雷尼镍催化还原糖类制取糖醇。工业上采用镍存在下高压催化氢化还原或在碱性介质中电解还原的方法制取糖醇。糖的环形经反应生成糖苷后，一般很难还原为糖醇。

糖醇少量存在于自然界中。一般是无色结晶，溶解度不及相应的糖类。有甜味，入口吸热，有清凉感。可以食用，且能为人体吸收代谢。可用作甜味剂、有机合成原料。

醛糖的还原生成一个产物，但酮糖的还原新生成一个立体中心，可以有两种产物。例如D-果糖经还原可生成D-甘露糖醇和D-葡萄糖醇。有些糖醇因为分子对称性，成为内消旋体，因此比相应的醛糖要少几个异构体。

Sugar alcohols (also called polyhydric alcohols, polyalcohols, alditols or glycitols) are organic compounds, typically derived from sugars, that comprise a class of polyols. Contrary to what the name may suggest, a sugar alcohol is not a sugar nor an alcoholic beverage. They are white, water-soluble solids that can occur naturally or be produced industrially from sugars. They are used widely in the food industry as thickeners and sweeteners. In commercial foodstuffs, sugar alcohols are commonly used in place of table sugar (sucrose), often in combination with high intensity artificial sweeteners to counter the low sweetness. Xylitol is perhaps the most popular sugar alcohol due to its similarity to sucrose in visual appearance and sweetness.