Ferulic acid is a hydroxycinnamic acid, a type of organic compound. It is an abundant phenolic phytochemical found in plant cell wall components such as arabinoxylans as covalent side chains. It is related to trans-cinnamic acid. As a component of lignin, ferulic acid is a precursor in the manufacture of other aromatic compounds. The etymology is from the genus Ferula, referring to the giant fennel (Ferula communis).

Ferulic acid is found in the seeds of coffee, apple, artichoke, peanut, and orange, as well as in both seeds and cell walls of commelinid plants (such as rice, wheat, oats, the Chinese water chestnut (Eleocharis dulcis) and pineapple). Often in the form of chlorogenic acid.

Ferulic acid, being highly abundant, may be useful as a precursor in the manufacturing of vanillin, a synthetic flavoring agent often used in place of natural vanilla extract. However, biotechnological processes may be the most efficient method to use ferulic acid as a precursor, and as such, research is still ongoing.