Objective: Unilateral sensorineural hearing loss (USNHL) is known to impact on school performance and social skills during childhood, but the etiologies remain unclear. The aim of this study was to assess various etiologies and to study the clinical contexts in this population. Methods: The study is a retrospective review. Characteristics of hearing loss (HL), audiometric parameters, imaging, and genetic and medical contexts were analyzed. Results: Eighty children were included. USNHL was profound in 68%, could be progressive in 19%, and become bilateral in 7.5% of cases. Inner ear malformations were identified in 41% of cases; cochlear nerve deficiency (CND) was frequent (33%). Cytomegalovirus (CMV) infection and genetic syndromes were confirmed in 10 and 6% of cases, respectively. Conclusion: Long-term hearing follow-up remains useful in USNHL as it can become bilateral. Looking to etiology, MRI should be the gold standard, as CND is frequently observed and screening for CMV infection should be systematic. Genetic etiologies appear to be different compared to bilateral HL. Further genetic research in this domain is needed.