Objective: To systematically review case reports of psychosis related to withdrawal or overdose of baclofen, which is a gamma-aminobutyric acid (GABA) B agonist. Methods: PubMed, MEDLINE, CINAHL, and PsychINFO were searched to identify articles related to psychosis secondary to withdrawal or overdose of baclofen using the terms 'baclofen' and ' psychosis'. Comparisons were made between cases in terms of concomitant antipsychotic use, diagnosis of delirium, and evidence of association. Quality of case reports was assessed using the CARE Case Report Guidelines checklist. Results: In total, 34 patients from 28 case reports were reviewed. Twenty-three patients experienced psychosis upon baclofen withdrawal; among them, 18 had resolution of psychosis upon reinitiation of baclofen, whereas antipsychotic monotherapy was less successful (only four of eight patients responded). An additional baclofen withdrawal period led to recurrence of psychotic symptoms in four of seven patients. Eleven patients had psychosis on induction or after overdose of baclofen; among them, four patients had resolution of psychosis upon cessation of baclofen. The mean quality of the case reports was 6.4 of 13. Conclusion: Considering its GABAergic agonism, along with evidence of psychosis on induction or withdrawal, baclofen may have some antipsychotic and pro-psychotic properties.