Bupropion, sold under the brand names Wellbutrin and Zyban among others, is a medication primarily used to treat major depressive disorder and to support stopping smoking. It is an effective antidepressant on its own, but is also used as an add-on medication in cases of incomplete response to first-line SSRI antidepressants. Bupropion is taken in tablet form and is available only by prescription in most countries.

Common side effects include dry mouth, trouble sleeping, agitation, and headaches. Serious side effects include an increased risk for epileptic seizures and suicide. The risk of seizures caused the drug to be withdrawn from the market for some time and then the recommended dose to be reduced. In comparison to some other antidepressants, it does not cause as much sexual dysfunction or sleepiness, and may result in weight loss. It is unclear if use during pregnancy or breastfeeding is safe.

Bupropion is an atypical antidepressant. It acts as a norepinephrine–dopamine reuptake inhibitor (NDRI) and a nicotinic receptor antagonist. Chemically, bupropion is an aminoketone that belongs to the class of substituted cathinones and is similar to phenethylamines.

Bupropion was first made by Nariman Mehta in 1969 and patented by Burroughs Wellcome in 1974. It was first approved for medical use in the United States in 1985. It was originally called by the generic name amfebutamone, before being renamed in 2000. In the United States the wholesale cost per dose is less than US$0.50 as of 2018. In 2016 it was the 28th most prescribed medication and 4th most prescribed antidepressant in the United States with more than 23 million prescriptions.