Background <p>Postoperative sleep disturbance (PSD) is a prevalent postoperative complication that significantly impacts patients’ recovery, particularly after thoracoscopic lung surgery .</p> Methods <p>This prospective, single center, randomized controlled trial included 117 adult patients aged 18–65 years who underwent elective thoracoscopic lung surgery. They were randomly divided into three groups: 1.0&#xa0;µg/kg dexmedetomidine nasal spray (Group D), 2.0&#xa0;µg/kg dexmedetomidine nasal spray (Group HD), and placebo group (Group P). Dexmedetomidine nasal spray or saline (the same device) was administered to the nasal cavity at 21:00–21:30 on the night before surgery, the night of surgery, and the first day after surgery. The primary outcome of this study was the incidence of postoperative sleep disturbance on postoperative day (POD) 1. PSD was defined as a Numeric Rating Scale (NRS)-sleep score of 6 or higher or an Athens Insomnia Scale score of 6 points or higher.</p> Results <p>On the night of surgery, the incidence of PSD in Groups D and HD was lower than that in Group P (30.8%vs.25.6%vs.69.2%, <i>P</i> &lt; 0.001). The NRS-Sleep score of patients in Groups D and HD were significantly higher than those in Group P(4[3,6]vs.4[3,5]vs.5[4,7]; <i>P</i> &lt; 0.001). Furthermore, the Quality of Recovery−15 scores were significantly higher in the Group HD than in the Group P on POD 1 (100.41 ± 8.73 vs.95.49 ± 6.20; <i>P</i> = 0.013) and POD 3 (112.74 ± 7.77vs.107.56 ± 7.06; <i>P</i> = 0.003).</p> Conclusion <p>Perioperative administration of dexmedetomidine nasal spray can effectively improve sleep quality on the night after surgery and improve the quality of recovery after thoracoscopic lung surgery .</p> Trial registration <p>Chinese Clinical Trial Registry (clinical trial number: ChiCTR2500099569, Date of Registration: March 25,2025).</p>