Introduction <p>Sulforaphane, an isothiocyanate derived from cruciferous vegetables (e.g., broccoli sprouts), has been explored for its antioxidant and anti-inflammatory properties. This is the first systematic review and meta-analysis to explore the therapeutic potentials of sulforaphane in schizophrenia.</p> Methods <p>We searched PubMed, Scopus, Web of Science, and Cochrane Central for studies from inception to April 2025. We included randomized controlled trials (RCTs) evaluating the efficacy of sulforaphane in schizophrenia. The primary outcomes were changes in the Positive and Negative Syndrome Scale (PANSS) total and its subscales. Secondary outcomes included cognitive measures, metabolic markers, and safety.</p> Results <p>Four RCTs with 369 schizophrenia patients were included. Sulforaphane did not significantly improve PANSS total or positive symptom scores at the latest follow-up (ranging from 24 weeks to 18 weeks) or at a consistent 12-week time point. However, a modest improvement in negative symptoms was found at 12 week- time point (MD= -1.06; 95% CI: -1.95 to -0.16; <i>p</i> = 0.02), which was not maintained at the latest follow-up. General psychopathology scores improved significantly (MD= -1.5; 95% CI: -2.78 to -0.23; <i>p</i> = 0.02). No cognitive benefits were observed. Sulforaphane led to significant reductions in metabolic markers, including LDL, triglycerides, and cholesterol. Discontinuation rates were lower in the sulforaphane group (RR = 0.68; 95% CI: 0.49 to 0.95; <i>p</i> = 0.02).</p> Conclusion <p>The study provides initial insights into sulforaphane’s potential therapeutic effects in schizophrenia, showing modest improvements in general psychopathology and negative symptoms, with favorable metabolic changes and lower discontinuation rates. Due to limited data and heterogeneity, the study findings should be interpreted with caution.</p> Clinical trial number <p>Not applicable.</p>