Switzerland goes to the polls on Sunday, June 14, to vote on whether to cap its population at 10 million people in a referendum some have likened to a "Swiss Brexit", part of a longtime push by right-wing leaders to cap the number of foreigners who migrate to the rich and economically vibrant Alpine country.

It could be a close contest, with the most recent poll showing 47% in favour and 52% against.

The initiative is backed by the populist Swiss People’s Party, which has the most seats in parliament.

Concern about rapid growth in Switzerland's population, which climbed to 9.1 million last year from 7.3 million in 2002, and its impact on public infrastructure has fed support for the proposal.

A self-inflicted wound, or salvation for Swiss-ness?

Supporters of the cap say the way of life has been strained under demographic growth and the expanding population is testing local infrastructure, roads and public transport to the limits, as well as driving up rents and crime.

Critics say passage would amount to a self-inflicted wound, arguing that Switzerland benefits from closer EU ties, and gets needed labor, expertise and skills from foreigners in sectors like healthcare, finance, pharmaceuticals and technology.

The federal government and parliament oppose the idea – and so do many businesses and employers, who fear an economic blow should the proposal succeed. They worry a "yes" vote would limit Switzerland's access to skilled labour and damage relations with the European Union, its biggest export market.

"As a Swiss citizen, it concerns me very much for the future of our country and its prosperity," said Martin von Moos, CEO of luxury hotels Belvoir in Ruschlikon and Sedartis in Thalwil, near Zurich.

"If we lost all of our foreign staff, the hotel simply wouldn't function," he said, noting nearly half of his 115 staff came from outside Switzerland.

Molecular Partners, a Zurich-based biotech company – more than half of whose roughly 120 staff are non-Swiss – said it was already tough to get the people it needed.

"I think if we said we could only hire out of the Swiss talent pool, or if we could only collaborate with the Swiss companies, it would basically be a showstopper," said Daniel Steiner, senior vice president of targeted radio therapeutics at the company.

"We may be forced to move things out of Switzerland."

Population 'keeps spiralling upwards'

The Swiss population had grown to 9.1 million by the end of 2025, from 7.3 million when free movement of people between Switzerland and the European Union was introduced in 2002.

The 38-country Organization for Economic Cooperation and Development has reported that Switzerland had a foreign-born population of 32% as of 2024.

"Switzerland is a small country with a limited territory, and it has experienced the highest population growth in recent years," said SVP lawmaker Yvan Pahud. "What we want is to protect what we love, to ensure that Switzerland remains a wonderful place to live in."

Knonau has seen its population leap almost 150% to 2,514 since 1990. That compares with a rise of 36% for Switzerland and 8% for the EU.

"It just keeps spiralling upwards, at some point there must be a stop," said Peter Zuercher, 77, a retired technician in Knonau who backs the initiative. "We need a certain amount of immigration, but what's happening now is too much."

'Switzerland is still the same size'

Referendums are a cornerstone of Swiss politics, with voters heading to the polls four times a year to decide on various national and regional issues.

Under the latest proposal, if Switzerland's population exceeded 9.5 million – a milestone that is forecast for 2031 – the government would be required to take measures to prevent it reaching 10 million, which it is forecast to hit in 2042.

At the 10 million threshold, Bern would be required to terminate international accords that encourage population growth.

That includes the agreement with the EU allowing free movement of people, a condition of the complex web of Swiss accords with Brussels that give the country access to the European single market.

Claude Maurer, chief economist at BAK Economics, a research institute, said if Bern abandoned its bilateral accords, growth would slow, while inflation, driven higher by wage increases, could trigger higher interest rates.

Thomas Matter, another SVP lawmaker and banker, dismissed the concerns as scaremongering.

Only one out of 10 immigrants were workers with sought-after skills and the rate of GDP growth per head had declined since the increase in immigration, Matter said.

"We are not against immigration, but it has to be moderate and controlled so we bring in the right people," he said. "Before we had qualitative immigration, now we have quantitative immigration. Switzerland is still the same size as it was in 1848, and more and more people are living in the same space."

Migration long an issue across Europe

International migration has long been a sensitive issue in Europe, as nations grapple with an aging population and increasing anti-foreigner sentiment.

While that sentiment in other European countries centers on migrants from the developing world, most foreigners in Switzerland are Europeans.

Swiss voters have repeatedly tackled the immigration issue over the last half-century.

Only one such referendum – "Against mass immigration" in 2014 – narrowly passed, after campaigners raised concerns about overpopulation and rising numbers of Muslims in the country.

No country has ever voted to limit its population, said Philippe Wanner, an expert in demography at the University of Geneva, though some countries have had policies to curb population growth.

Many nations limit immigration, said Etienne Piguet, a professor at the Institute of Geography at the University of Neuchatel.

In Switzerland, the debate has raged for decades. On Sunday, voters will give their latest answer.