A case of tardive dyskinesia due to olanzapine treatment. Tardive dyskinesia (TD) is a complex of abnormal reflex movements involving the tongue, body, arms, and legs after the use of antipsychotics. These movements are generally choreiform, athetoid, or rhythmic. According to the DSM-IV, these reflex movements must have been present for at least four weeks and the antipsychotic medication should have been used for at least 3 months (at least 1 month if the patient is 60 years or older) for the TD to have been caused by the use of antipsychotic drugs. TD development is much more common with the use of high potency classic antipsychotics that block dopamine receptors in the nigrostriatal area and the risk increases as the dosage increases. Atypical antipsychotics such as risperidone, olanzapine, quetiapine, and ziprasidone have lower risks for TD development. Olanzapine has been used in the treatment of cases where tardive dyskinesia occurred due to other psychotropic medications and there are rare case reports about olanzapine caused tardive dyskinesia. In this report, a case of tardive dyskinesia due to olanzapine use in a 24 year-old male patient is discussed in the light of existing literature.