ObjectiveSleep disturbance and cognitive impairment are common in depression. Trazodone is often used for sleep problems and may improve cognition by modifying sleep architecture. However, its effects on specific polysomnography-derived sleep stages remain unclear. This systematic review and exploratory meta-analysis aimed to investigate trazodone’s effects on sleep architecture in patients with depression and sleep disorders.MethodsSeven databases were searched for interventional studies published up to October 2025. Random-effects models were applied to estimate pooled mean differences (MDs) and risk ratios (RRs), as appropriate.ResultsEight studies involving 980 patients were included: five randomized controlled trials and three single-arm studies. Compared with baseline, trazodone was associated with increased total sleep time and sleep efficiency, and with reduced sleep latency. Regarding sleep architecture, trazodone was linked to reduced non-rapid eye movement sleep stage 2 (N2) proportion (MD = −9.09, 95% CI −16.60 to −1.59, P = 0.017) and increased slow wave sleep (SWS) proportion (MD = 8.05, 95% CI 3.42 to 12.68, P = 0.001). No significant effects were observed for wake after sleep onset, NREM stage 1 percentage, rapid eye movement sleep percentage (REM), and REM sleep latency. Secondary outcomes suggested reduced HAMD-17 scores and higher response rates versus placebo, but more adverse events, especially somnolence and dizziness, with trazodone.ConclusionTrazodone may improve objective sleep continuity and may be associated with changes in sleep architecture, including increased SWS and reduced N2 sleep, in patients with depression, without significantly altering REM sleep. These potential benefits should be weighed against increased adverse events.Systematic Review Registrationhttps://www.crd.york.ac.uk/PROSPERO/, identifier CRD420251173354.