Valproic acid is a chemical compound that has found clinical use as an anticonvulsant and mood-stabilizing drug, primarily in the treatment of epilepsy and bipolar disorder; but also used to treat migraine headaches and schizophrenia. In epileptics, valproic acid is used to control absence seizures, tonic-clonic seizures (grand mal), complex partial seizures, and the seizures associated with Lennox-Gastaut syndrome.

Related drugs include the sodium salts sodium valproate, used as an anticonvulsant, and a combined formulation, valproate semisodium, used as a mood stabilizer and additionally in US also as an anticonvulsant.

Valproate is believed to affect the function of the neurotransmitter GABA (as a GABA transaminase inhibitor) in the human brain, making it an alternative to lithium salts in treatment of bipolar disorder.