Hundreds of people rallied in Taiwan's capital on Sunday (October 25).
They were calling for China to release 12 Hong Kong citizens arrested at sea by mainland authorities.
The rally is part of a global campaign to support the pro-democracy movement in the financial hub.
"Hong Kong's today is Taiwan's tomorrow," said one protester, "our Taiwan will become Hong Kong if we don't step forward."
The 12 were arrested in August for alleged illegal entry into mainland China after setting off from Hong Kong in a boat bound for Taiwan.
Hong Kong's Security Bureau has said all 12 were suspected of committing crimes including manufacturing or possessing explosives, arson and rioting in Hong Kong.
Authorities added that ten of them were on bail and not allowed to leave Hong Kong.
Beijing considers Taiwan its territory and has never renounced the use of force to bring the island under its control.