Finasteride is a 5-α reductase inhibitor indicated for the treatment of androgenetic alopecia and benign prostatic hyperplasia (BPH). Finasteride has been associated with various adverse events, such as erectile dysfunction, fatigue, cognitive impairment, sleep disturbances, including insomnia, depression, and suicidal behavior. These symptoms are sometimes considered features of the "post-finasteride syndrome" (PFS) and are also encountered in obstructive sleep apnea (OSA). The overlapping clinical features of PFS and OSA suggest that OSA could possibly play a mediating role in some of the PFS-related symptoms. There are no reported studies of the association of finasteride use and OSA. The objective of this study was to determine whether finasteride use is associated with a potential safety signal of OSA compared to a baseline potential safety signal for all other drugs in the US Food and Drugs Administration Adverse Event Reporting System (FAERS) database. A case by non-case disproportionality approach was used, whereby a reporting odds ratio (ROR) with 95% confidence interval (CI) was calculated. Cases of finasteride-associated OSA were compared to a reference potential safety signal of OSA with all other drugs in the database. A similar calculation was carried out for finasteride-associated insomnia to confirm previous reports of a greater than expected reporting of insomnia with finasteride use. A significant disproportionality (ROR = 5.65 [95% CI 4.83-6.62, z = 21.56, P < 0.0001]) in reporting of OSA with the use of finasteride was observed. The potential safety signal for OSA with finasteride remained significantly higher when finasteride use for hair loss and BPH was examined separately. Finasteride use was associated with a greater than expected reporting of insomnia (ROR = 1.93 [95% CI 1.77-2.09, z = 15.958, P < 0.0001]). A limitation of this study is that selection bias is inherent in FAERS and adverse events could be underreported. Finasteride use may be associated with a potential safety signal for OSA. Patients complaining of PFS-related symptoms may benefit from a further sleep evaluation to rule out underlying OSA.