Guillain-Barré syndrome (GBS) is a group of clinical syndromes involving acute polyneuropathy secondary to an immune-mediated process. Although affected children generally tend to have a good prognosis, a small subset of children experience residual symptoms that require lengthy and costly rehabilitation. Therefore, we aimed to describe the clinical findings of children with GBS and to investigate factors associated with their outcomes. Methods: A retrospective study was conducted of previously healthy children ≤18 years of age diagnosed with GBS and admitted to Pusan National Children's Hospital between 2009 and 2018. Results: Of the 38 patients included in the study (23 boys [60.5%]; median age, 4.3 years [interquartile range, 2.8 to 9.7 years]), 28 (73.7%) fully recovered without any residual symptoms, while 10 (26.3%) had residual symptoms more than 6 months after the onset of GBS. The presence of autonomic dysfunction and a ≥50% decrease in compound muscle action potential (CMAP) amplitude from the lower limit of normal were associated with functional deficits at 6 months. Age, sex, type of antecedent illness, cranial nerve involvement, the need for mechanical ventilation, and the subtype of GBS were not significantly associated with functional outcomes. Post-gadolinium enhancement of nerve roots was seen in 71.1% of patients on initial spine magnetic resonance imaging (MRI). Conclusion: Contrast enhancement of nerve roots on MRI was the most helpful initial finding for diagnosing GBS. The presence of autonomic dysfunction and a ≥50% decrease in CMAP from the lower limit of normal were poor prognostic factors for functional outcomes.