Haemophagocytic lymphohistiocytosis (HLH) and macrophage activation syndrome (MAS) life-threatening systemic hyperinflammatory syndromes that can develop in most inflammatory contexts. We present a case of a 15-year-old boy persistent fever, generalized weakness, and altered mental status with elevated inflammatory markers & with the clinical history, examination & investigation findings, we present a compelling case of Dengue-associated Hemophagocytic Lymphohistiocytosis.