Pharyngeal-cervical-brachial (PCB) variant of Guillain-Barré Syndrome (GBS) is characterized by weakness in cervicobrachial and oropharyngeal region, together with areflexia of upper limbs. Being an uncommon variant, it is often misdiagnosed as other neurological conditions resembling GBS. Although most of the cases occur as a post-infectious complication, no reports describing its development following dengue-chikungunya co-infection have been documented. A young female presented with a progressive history of swallowing difficulty, bilateral arm weakness and neck weakness. Three weeks earlier, she was presented with clinical features corresponding to dengue and was symptomatically treated. Currently, hypotonia and decreased muscle strength were observed in both upper limbs and neck. Detailed investigation revealed the presence of Immunoglobulin M (IgM) antibodies against dengue antigen (NS 1) and Chikungunya virus (CHIKV), confirming the possibility of previous dengue-chikungunya co-infection. Nerve conduction studies and electromyography of upper limbs pointed towards findings consistent with the early stages of acute motor demyelinating and possible axonal neuropathy. The detection of antiganglioside antibodies (anti-GT1a antibodies), confirmed the diagnosis of the pharyngeal-cervical-brachial variant of GBS. A five days treatment of intravenous immunoglobulin (IVIG) along with physical rehabilitation was started which led to significant improvement and the patient was discharged after 15 days. PCB is an unfamiliar variant of GBS for many clinicians. Diagnosis can be made by a thorough history, clinical examination and investigations that can rule out other potential causes of cervicobrachial and oropharyngeal weakness. It also necessitates careful monitoring and followups after mono- and co-arboviral infections to prevent any debilitating neurological complications.