One person was seriously injured and had to be removed through the upper rear window of a bus, the South China Morning Post reported.
Police said one double-decker bus hit the back of another bus loading passengers at a bus stop in the Wan Chai district of Hong Kong Island. The force of the crash sent the second bus into another double-decker bus at the stop.
Most of the passengers received only minor injuries, The Standard reported.
It was the second major bus crash in Hong Kong in a week.