With nationalist parties topping polls in Britain, France and Germany, the Dutch national election is a test of whether populism can expand its reach or whether it has peaked in parts of Europe.
Wilders led his party to a stunning first-place finish in the previous election in 2023 and formed an all-conservative coalition - although his partners refused to endorse him as prime minister.
He brought the government down in June over its refusal to adopt his hardline anti-refugee measures.
Opinion polls show Wilders' Freedom Party (PVV) winning but only by a narrow margin, with the four centrist parties spanning the mainstream right and left all finishing within a few seats of the bleached-blond admirer of US President Donald Trump.
All four, including the centre-right VVD and Christian Democrats, have said they would not enter into a coalition with Wilders and his PVV party, meaning he would likely be blocked from power unless he wins by an unexpectedly wide margin.
Polling stations opened early on Wednesday in some locations to make it easier for commuters to vote.
The first exit poll, which historically has proven to be accurate, will be released when voting ends at 9pm.
Dutch elections have become increasingly unpredictable and building stable coalitions is a fraught task which can take weeks or months.
Opinion polls showed nearly half the electorate was still undecided days ahead of the vote.
Wilders, one of Europe's longest-serving populist leaders, is renowned for his anti-Islam stance and lives under constant protection due to death threats.
He proposes saving funds by denying all asylum requests - which would violate EU treaties - sending male Ukrainian refugees back to Ukraine, and halting development aid to finance energy and healthcare benefits.
The PVV has seen some of its support siphoned away by the Christian Democrats, whose new leader Henri Bontenbal is campaigning on a pledge of government stability and traditional values.
Also on the rise is the Centrist D66, which has scored with the positive messaging of its polished frontman Rob Jetten, who promises to build more houses and spend more on education.
Analysts say that Wilders' ebbing support reflects voter frustration over chaotic infighting in the last coalition.
His gushing praise of Trump's leadership and the US president's perceived willingness to test the limits of US democracy also unsettles some voters.
The stated refusal of mainstream parties to enter into an alliance with Wilders may give rise to tactical voting in favour of other conservative parties, political analysts said.
