The victim and another 19-year-old man were found with stab wounds, with the deceased suffering a fatal chest wound.
Paramedics attempted to revive him, but he was pronounced dead at the scene.
The second teenager was taken to hospital in a stable condition with an arm injury.
It is unclear whether the two men knew each other.
Investigation Underway
A crime scene has been established, and officers from the Mount Druitt Police Area Command, assisted by the State Crime Command’s Homicide Squad, are investigating the incident.
The bus interchange remains closed as police gather evidence and review security footage.
Anyone with information is urged to come forward and assist the police investigation.
A report will be prepared for the coroner.
The motive behind the stabbing is currently unknown, and police are working to determine the circumstances surrounding the incident.