The most seriously injured were taken to Lisbon’s São José hospital, and all of the victims on the Yellow Bus were identified as foreign nationals.
According to reports, two victims were incarcerated in the vehicle and had to be freed by firefighters. One was reportedly a 50-year-old Belgian national.
Emergency rescue services were called out at around 9.50am on Tuesday morning after the alarm was raised that a bus had crashed into a tree in the Restauradores neighbourhood.
The accident also involved a car that was hit by the open-top bus.
Police were working to establish what caused the bus to run into a tree on one of the busiest stretches in the capital.
Twenty-one firefighters and six vehicles were dispatched to the scene along with INEM emergency medics and PSP police.