Sonia Bibi was admitted to Nishtar Hospital in Multan last month with over 50 per cent burn injuries. The doctors tried their best to save her life but without any success, police said.
"She died early today in the hospital," a police official Akram Rana said.
Sonia told police in hospital that she was set ablaze by her former lover after she turned down his marriage proposal.
Police has arrested the 24-year-old suspect accused of setting Sonia on fire in a remote village in Multan district in Punjab province.