Guillain–Barré syndrome (GBS) is an acute, immune-mediated inflammatory polyradiculoneuropathy. Its most common symptom is limb muscle weakness, which usually occurs symmetrically, typically involving the lower limbs. There is a weakening or abolition of deep reflexes, and radicular pain, most often in the lumbar or intercostal regions. In half of patients, facial muscle weakness can be observed. In most cases, especially at the onset of symptoms, there is paraesthesia involving the distal parts of the lower extremities and, in rarer cases, also the distal parts of the upper extremities. The uncharacteristic and varied symptoms mean that the diagnosis can present some difficulties. This review discusses the latest updates on the diagnosis and treatment of Guillain–Barré syndrome based on the 2023 European Academy of Neurology/Peripheral Nerve Society (EAN/PNS) criteria. The guidelines emphasise a systematic approach to clinical evaluation, diagnostic testing, and therapeutic strategies, using robust evidence and best-practice recommendations. Key points include the role of preceding infections, particularly Campylobacter jejuni, in the pathogenesis of the syndrome, and the identification of diagnostic subtypes, such as acute inflammatory demyelinating polyradiculoneuropathy, acute motor axonal neuropathy, and Miller Fisher syndrome. Electrodiagnostic tests have been recognised by the EAN/PNS as essential tools for diagnosing Guillain–Barré syndrome, while plasmapheresis and intravenous immunoglobulin remain the pillars of treatment. The article highlights the importance of early intervention and differentiation of Guillain–Barré syndrome from chronic neuropathies for optimal outcomes.