Police have detained the Swedish climate activist and dozens of others during what they said was a banned protest.
ADVERTISEMENTPolice said the protesters had partially blocked a road in the Dutch city.
Thunberg was seen flashing a victory sign as she sat in a bus used by police to take detained demonstrators from the scene of the demonstration against Dutch subsidies and tax breaks to companies linked to fossil fuel industries.
The Extinction Rebellion campaign group said before the demonstration that the activists would block a main highway into The Hague, but a heavy police presence, including officers on horseback, initially prevented the activists from getting onto the road.
A small group of people managed to sit down on another road and were detained after ignoring police orders to leave.
'We are facing an existential crisis'
Thunberg defended the rights of people to protest.
''We are here because we are facing an existential crisis. We are in a planetary emergency, and we are not going to stand by and let people lose their lives and livelihood and be forced to become refugees when we can do something, '' she said.
When asked why the group would not move to a grassed area to allow motorists to use the road, Thunberg said, ''We are facing an existential emergency, and we must do everything we can''.
Extinction Rebellion activists have blocked the highway that runs past the temporary home of the Dutch parliament more than 30 times to protest the subsidies.
In February, Thunberg, 21, was acquitted by a court in London of refusing to follow a police order to leave a protest blocking the entrance to a major oil and gas industry conference last year.
She has repeatedly been fined in Sweden and the UK for civil disobedience in connection with protests.
