Emerging evidence suggests a link between obstructive sleep apnea (OSA) and lung cancer, but tobacco smoking may confound this relationship. This prospective study evaluated the prevalence and clinical features of OSA among never-smokers with lung cancer. Newly diagnosed, never-smoking lung cancer patients underwent respiratory polygraphy before cancer treatment. Of 77 enrolled, 67 patients were analyzed (age, 65 years; women, 83.6%; body mass index, 24 kg/m²). OSA (respiratory event index [REI] ≥ 5/hour) was present in 47.8% of the patients-specifically, in 29.4%, 60.0%, 65.0%, and 44.0% of the patients with stage I, II, III, and IV lung cancer, respectively (P = 0.175). 20.9% of the patients had moderate-to-severe OSA (REI ≥ 15/hour). Adenocarcinoma was the predominant histologic type (97%), and 67.2% had advanced-stage (stage III/IV) lung cancer. REI and the percent night time with oxygen saturation < 90% (T90) did not differ between the patients with advanced- and early-stage lung cancer (REI: 5.3/hour vs. 3.0/hour, P = 0.171; T90: 0.6% vs. 0.2%, P = 0.139). In multivariable logistic regression analyses, neither REI nor T90 was associated with advanced-stage lung cancer. Nearly half of never-smokers with lung cancer had OSA, with many having moderate-to-severe disease, underscoring the need for proper diagnosis and management.Clinical Trial Registration: NCT05224180.