The incident happened at about 10:15 am (local time) when the tourists - three men and five women - were going up on the escalator at Phaya Thai station.
According to the Bangkok Mass Transit System (BTS), they were planning to board a train to Bearing station.
They were busy chatting with each other before they all tumbled down, the Bangkok Post reported.
There were no children. BTS staff provided first aid to the wounded commuters, the report said.