Malic acid is an organic compound with the formula HO2CCH2CHOHCO2H. This dicarboxylic acid is the active ingredient in many sour or tart foods. The salts and esters of malic acid are known as malates. Malate anion is an intermediate in the citric acid cycle along with fumarate. Ca. 1M kg/y are produced by the hydration of maleic anhydride.

Malic acid, when added to food products, is denoted by E number E296. Malic acid is the source of extreme tartness in so-called "extreme candy", for example Mega Warheads or Sour Punch candies. It is also used with or in place of the less sour citric acid in sour sweets such as Jolly Ranchers, SweeTarts and Salt & Vinegar flavor potato chips. These sweets are sometimes labeled with a warning that excessive consumption can cause irritation of the mouth.