糖醛酸（Uronic acids），为糖酸的一种，同时拥有醛基及羧基等两种官能基。为糖类的终端碳上的羟基氧化为羧基而成。如果被氧化的是醛基，则称为醛糖酸（aldonic acid，化学结构中并无醛基），那如果两边都被氧化成羧基的话，则称为醛糖二酸（aldonic acid）。

糖醛酸的命名是依照其还原态糖类，然而有些糖醛酸并不只有一种还原态，而有差向异构体（epimers）。六碳的糖醛酸被称为己糖醛酸（hexuronic acids）。

For hexuronic acid, i.e. the older name of Vitamin C, see Ascorbic acid.

Uronic acids (/jʊˈrɒnᵻk/) are a class of sugar acids with both carbonyl and carboxylic acid functional groups. They are sugars in which the terminal carbon's hydroxyl group has been oxidized to a carboxylic acid. Oxidation of the terminal aldehyde instead yields an aldonic acid, while oxidation of both the terminal hydroxyl group and the aldehyde yields an aldaric acid. The names of uronic acids are generally based on their parent sugars, however some of the most common do not have direct parents, and are formed by epimerization (e.g., iduronic acid is an epimer of glucuronic acid). Uronic acids that have six carbons are called hexuronic acids.