Political parties are banned from the election, and voters chose from individual candidates who are almost all loyal to King Mswati III.
Election campaigning was discreet, with no rallies, no manifestos and just a handful of candidate posters on main road junctions outside the capital Mbabane.
With 530,000 eligible voters, early results are expected on Saturday.
The tiny African kingdom of eSwatini, ruled by an absolute monarch, voted Friday in polls that critics call a sham but supporters say are a unique blend of tradition and politics.
Political parties are banned from the election, and voters chose from individual candidates who are almost all loyal to King Mswati III.
The king is one of the world's last absolute rulers — wielding complete control over the parliament and government, as well as over the judiciary, civil service and security forces.
Poverty
Mswati, who has 14 wives and more than 25 children, has a reputation for lavish spending on planes and palaces, while 63 per cent of his subjects live below the poverty line.
Without warning or consultation, he changed the country's name from Swaziland to eSwatini ("land of the Swazis") in April.
"We know the person we are voting for," Zodwa Mabuza told AFP as she lined up to vote with her husband and daughter in the western constituency of Lobamba Lomdzala.
"The issues are job opportunities, proper roads and more food packages for the elderly."
Another voter who declined to be named said that "the parliament can talk all they want, but at the end of the day there is only one boss".
No political parties
The authorities say that the absence of political parties fosters a close link between citizens and elected representatives.
"To the critics, it is important to say that there is no 'one size fits all' democracy or system of government," Pholile Dlamini, deputy chair of the Elections and Boundaries Commission, told AFP.
"This system is a perfect fit because eSwatini is a modern-day country that has chosen to preserve its very rich cultures and traditions."
Winners from the 59 constituency ballots will take seats in parliament, along with 10 lawmakers that the king appoints directly.
He can veto legislation, appoints the prime minister and cabinet, and is constitutionally above the law.
"The election is a farce, of course," said Bheki Makhubu, editor of The Nation magazine, who spent 15 months in jail from 2014 to 2015 for contempt of court after exposing misconduct among judges.
"The king is the executive authority of all things, based on the presumption he is the wisest of us all.
"Swazi people either try to win royal attention to seek reward, or they keep their heads down."
Makhubu said he supported a reformed monarchy rather than a republic, as many Swazis would not accept the authority of an ordinary person.
Political parties were banned by the king's father in 1973, and still face severe restrictions despite a 2005 constitution that, in theory, guarantees their rights.
Campaign
Election campaigning was discreet, with no rallies, no manifestos and just a handful of candidate posters on main road junctions outside the capital Mbabane.
The Pudemo party, which was designated a terrorist organisation under draconian new laws in 2008, called for a boycott of the vote, describing it as "fixed" by the king.
Underlying tensions in eSwatini surfaced this week as thousands of protesters joined two days of trade union marches calling for public sector wage increases.
The demonstrations, which centred on the second city Manzini and were broken up by riot police using tear gas and water cannons, left several people injured.
"The key causes of public dissatisfaction are fiscal mismanagement, private spending by the king and widespread poverty," Michael Jones, an analyst at the London-based Fitch risk consultancy, told AFP, adding that the election offered little hope of policy change.
The Communist Party called for a boycott, describing the vote as "crude window dressing".
Observer missions
The Southern African Development Community bloc and African Union have deployed observer missions. But the EU and Commonwealth have not sent teams.
"I want to empower the nation by making the economy more sustainable," Charles Nkhanyeti, 50, who is standing for election, told AFP.
"There are some dissenting voices, but the king has much support. We like the election system and we want to make it work."
The country, landlocked between South Africa and Mozambique, suffers the highest HIV adult prevalence rate in the world at 27.2 per cent.
With 530,000 eligible voters, early results are expected on Saturday. The king is expected to appoint the prime minister within the next month.