Wilders, who is now trying to build a governing coalition, has vowed to close Dutch borders to immigrants and cut spending on climate change, cultural and foreign development programmes.
"I feel sad about the election results ... And I'm really worried about our country," said Sara Coster.
Another demonstrator, Jan Jaap van Oosterzee, 62, said he felt Wilders' win was "against every thing we're standing for, and that I'm personally standing for".
Wilders party "stands for exclusion of my colleagues, of my children, of denying climate change," he said.
Muslims, who make up around 5% of the Dutch population of almost 18 million people, have expressed shock at the election result.
Persons:
Geert Wilders, Wilders, I'm, Sara Coster, Jaap van Oosterzee, Oosterzee, Toby Sterling, Alexander Smith
Organizations:
Social, Freedom Party, Amnesty International, Greenpeace, Thomson
Locations:
Amsterdam, Netherlands, AMSTERDAM, Solidarity