OBJECTIVE: Laryngomalacia has been reported to contribute to the severity of obstructive sleep apnea (OSA) in children. It is unclear if surgical treatment of laryngomalacia improves polysomnography (PSG) outcomes in these patients. The objective of this study is to report the impact of supraglottoplasty on PSG parameters in children with laryngomalacia-related OSA. STUDY DESIGN: Retrospective case series. SETTING: Tertiary care medical center. SUBJECTS AND METHODS: Historical cohort study of consecutive children with laryngomalacia who underwent supraglottoplasty and who had undergone overnight PSG before and after surgery. RESULTS: Forty-one patients were included in the final analysis: 22 (53.6%) were male, and 19 (46.3%) were female. The mean ± SEM age of patients at preoperative PSG was 1.3 ± 0.89 years (range, 0.003-2.9). In entire cohort, the mean obstructive apnea-hypopnea index score was reduced from 26.6 events/h before supraglottoplasty to 7.3 events/h after surgery (P = .003). Respiratory disturbance index was reduced from 27.3 events/h before supraglottoplasty to 7.8 events/h after surgery (P = .003). The percentage of REM sleep decreased from 30.1% ± 2.4 to 24.8% ± 1.3 (P = .04). Sleep efficiency was improved (P = .05). CONCLUSION: Overall, supraglottoplasty significantly improved several PSG outcomes in children with laryngomalacia. However, mild to moderate OSA was still present postoperatively in most children. This suggested a multifactorial cause for OSA in this population.