Invasive Group A Streptococcus (GAS) disease is a serious condition that has multiple manifestations. A particularly severe form of invasive GAS disease is necrotising fasciitis (NF). The case-fatality rate of GAS NF is approximately 20%. Penicillin remains the antibiotic of choice when treating invasive GAS infections. Epidemiological studies have shown that clindamycin is effective in the treatment of deep infections that are caused by GAS. Clinicians should consider adding clindamycin to the beta-lactam antibiotic regimen when NF or myositis is present. Intravenous immunoglobulin appears to be a promising adjunctive therapy in the management of GAS NF. Consultations with surgeons and infectious disease specialists are imperative.