Montelukast is a leukotriene receptor antagonist, which is used to treat asthma, allergic rhinitis and exercise induced bronchospasm. The medicine is viewed as effective and is widely used, but rising reports of neuropsychiatric adverse drug reactions have raised concerns about its safety profile. Several post-marketing reviews and regulatory safety warnings have noted the potential link between montelukast and psychiatric adverse effects. The present study was designed to assess the neuropsychiatric adverse medication events related to montelukast by using pharmacovigilance data from the WHO VigiAccess database. A retrospective observational study was conducted to collect and analyze reported neuropsychiatric adverse events associated with montelukast medication. Reported side effects included anxiety, sadness, sleeplessness, nightmares, hostility, irritability, hallucinations and suicide ideation. Descriptive statistical analysis was applied to estimate the frequency and distribution of the reported adverse events. Insomnia (22.7%) and anxiety (20.3%) were the most commonly reported neuropsychiatric adverse medication reactions, followed by depression (16.0%) and nightmares (14.1%). Severe psychiatric adverse effects, such as hallucinations and suicidal ideation, were reported less frequently but were clinically relevant. The findings of this study echo prior indications that there may be an association between montelukast use and neuropsychiatric side effects. The study highlights the necessity of continued pharmacovigilance, adequate patient counseling and early detection of psychiatric problems during montelukast medication. Increased understanding of these adverse effects among health care providers may help enhance patient safety and appropriate usage of montelukast.