Haloperidol (sold under the tradenames Aloperidin, Bioperidolo, Brotopon, Dozic, Duraperidol (Germany), Einalon S, Eukystol, Haldol, Halosten, Keselan, Linton, Peluces, Serenace, Serenase, Sigaperidol) is a conventional, or typical, butyrophenone antipsychotic drug with pharmacological effects similar to the phenothiazines.

It is used in the treatment of schizophrenia and, more acutely, in the treatment of acute psychotic states and delirium. A long-acting decanoate ester is used as a long acting injection given two or three weekly to people with schizophrenia who have a poor compliance with medication and suffer frequent relapses of illness. In some countries this can be involuntary under Community Treatment Orders.

It was developed in 1957 by the Belgian company Janssen Pharmaceutica and submitted to first clinical trials in Belgium in the same year. After being rejected by U.S. company Searle due to side effects, it was later marketed in the U.S. by McNeil Laboratories.