A man with schizophrenia received regular haloperidol ester therapy, but his psychotic symptoms were not mitigated. A combination of zotepine and haloperidol was then used to relieve the psychotic symptoms. However, the patient developed spontaneous ejaculations, which occurred many times a day while undergoing haloperidol and zotepine therapy. These events were not preceded by sexual stimulation and were not associated with a pleasurable sensation. The discomfort disappeared after discontinuing zotepine. Zotepine-induced spontaneous ejaculation was, therefore, diagnosed. There are few reports of drug-related spontaneous ejaculation. Clinicians need to recognize the possibility of zotepine-related spontaneous ejaculation because sexual side effects have an impact on medical adherence.