Hypoglossal nerve stimulation (HNS) therapy (Inspire system) is intended for the treatment of patients with moderate to severe obstructive sleep apnea (OSA) who cannot be effectively treated with the first-line treatment options. Approximately 3 months after activation of HNS therapy, a fine-tuning sleep study is performed. To date, the standard of care involves an in-laboratory overnight titration PSG, which assesses the device settings and, if necessary, the stimulation strength will be adjusted based on observed respiratory events and/or snoring. Considering the growing patient population, the performance of these overnight titrations can become logistically challenging and labor-intensive. Recently, the feasibility of using a daytime PSG as an alternative to a conventional overnight PSG for titration of HNS therapy was demonstrated. The aim of this study is to further investigate this technique by performing a non-inferiority analysis of daytime versus overnight PSG for titration of HNS therapy in patients with OSA.