March 29, 2017 0318 GMT
Following last year's shock Brexit referendum, and Donald Trump's victory in the US, the Dutch vote is being closely watched to gauge support for populism in Europe ahead of key elections in France and Germany this year, AFP reported.
Wilders voted in a school in The Hague, mobbed by television cameras, just after final polls showed he was trailing the Liberal VVD party of outgoing Prime Minister Mark Rutte.
"Whatever the outcome of the election today the genie will not go back into the bottle. And this patriotic revolution, whether today or tomorrow, will stay," Wilders said.
Amid the tussle between Rutte and Wilders, many of the 12.9 million eligible voters were still hesitating between 28 parties in the running.
"This is a crucial election for The Netherlands," Rutte said as he voted. "This is a chance for a big democracy like The Netherlands to make a point... to stop this domino effect of the wrong sort of populism."
Rutte is bidding for a third term as premier of the country – one of the largest economies in the eurozone and a founding father of the European Union.
Final polls appeared to show Rutte consolidating a lead over Wilders, crediting the VVD with 24 to 28 seats – well down on its 40 outgoing seats.
After months leading the polls, Wilders has slipped recently and was seen barely clinging onto second place with between 19 and 22 MPs – up on the 12 MPs his Freedom Party (PVV) had before.
Wilders has pledged to close the borders to Muslim immigrants, shut mosques, ban sales of the Qu’ran and leave the EU.
"I see this rightwing populist making gains and I will not live in such a world," said Esther Zand, 52, who voted for Labour.
"He's a rather irritating gentleman," she added of Wilders.