Bupropion (INN; previously known as amfebutamone, Wellbutrin, Zyban) is an atypical antidepressant that acts as a norepinephrine and dopamine reuptake inhibitor, and nicotinic antagonist. Bupropion belongs to the chemical class of aminoketones and is similar in structure to the stimulant cathinone, to the anorectic diethylpropion, and to phenethylamines in general.

Initially researched and marketed as an antidepressant, bupropion was subsequently found to be effective as a smoking cessation aid. In 2006 it was the fourth-most prescribed antidepressant in the United States retail market, with more than 21 million prescriptions.

Bupropion lowers seizure threshold and its potential to cause seizures was widely publicized. However, at the recommended dose the risk of seizures is comparable to that observed for other antidepressants. Bupropion is an effective antidepressant on its own but it is particularly popular as an add-on medication in the cases of incomplete response to the first-line SSRI antidepressant. In contrast to many psychiatric drugs, including nearly all antidepressants, bupropion does not cause weight gain or sexual dysfunction.