Ms Hasina will serve another five years in office after her party the Awami League and its allies won 223 of 300 parliamentary seats contested.
With the main opposition Bangladesh Nationalist Party boycotting the poll, Ms Hasina's party and allies are expected to win the remaining seats as well.
The BNP alleged the poll was a sham.
Sunday's result comes after mass arrests of BNP leaders and supporters.
Official figures suggested a low voter turnout of about 40%, though critics say even those numbers may be inflated. In comparison, the last election in 2018 had a voter turnout of more than 80%.
Independents, almost all of them from the Awami League itself, won 45 seats and the Jatiya Party won eight seats. Results are expected to be announced officially later on Monday.
It is the fifth term in total for Ms Hasina, who first became prime minister in 1996 and was re-elected in 2009, remaining in power since.
"I am trying my best to ensure that democracy should continue in this country," she told reporters as she cast her vote.
Awami League general secretary Obaidul Quader told reporters that Ms Hasina had instructed party leaders and supporters not to hold victory processions or indulge in celebrations.
Human Rights Watch (HRW) estimates that nearly 10,000 activists were arrested after an opposition rally on 28 October turned violent, resulting in the deaths of at least 16 people and injuring more than 5,500. It accused the government of "filling prisons with the ruling Awami League's political opponents".
The Awami League has denied these accusations.Fears have been raised that this new victory for the Awami League could lead to de-facto one party rule.
Very few expect the government to relax its crackdown. More so, if opposition parties and civil society groups continue to raise questions over the legitimacy of the government.
The BNP boycotted the election after the Awami League rejected their demands for an independent caretaker government to preside over the polls.
Until then, "our peaceful and non-violent movement will vigorously continue," Tarique Rahman, the acting chairman of the BNP told the BBC by email from London where he has lived since 2008.
Mr Rahman, who is the son of Ms Hasina's bitter rival, former Prime Minister Khaleda Zia, also denied accusations that BNP party workers were involved in arson attacks in the run up to the poll.
Ms Zia is currently under house arrest on charges of corruption.
In 2018 Mr Rahman was convicted in absentia of orchestrating a grenade attack on a campaign rally for Ms Hasina in 2004 and sentenced to life imprisonment. Ms Hasina was injured and at least 20 others were killed in that incident.
"All allegations against me are baseless and rooted in political vengeance," he said.
The BNP also called on people to not cast their votes.But Ms Hasina's supporters insist she has provided much-needed political stability for Bangladesh.
"We have continued the democratic process which has given this political stability. I think the world should credit Sheikh Hasina for that," says Law Minister Anisul Huq.
Ms Hasina's single biggest achievement in the past 15 years "is the confidence that she has ushered in in the minds of the people of Bangladesh. They have come to believe in themselves," he added.
Bangladesh's Prime Minister Sheikh Hasina has secured her fourth straight term
Bangladesh under Ms Hasina presents a contrasting picture. The Muslim-majority nation, once one of the world's poorest, has achieved credible economic success under her leadership since 2009.
It's now one of the fastest-growing economies in the region, even surpassing its giant neighbour India. Its per capita income has tripled in the last decade and the World Bank estimates that more than 25 million people have been lifted out of poverty in the last 20 years. It is also the world's second largest garment producer after China.
But the economy spun into turmoil in mid-2022 following the pandemic and a global economic slowdown.With rising inflation and conditions for an IMF loan it took earlier kicking in, the government may struggle to tackle public fallout.
International pressure is also kicking in.
In September, Washington began imposing visa restrictions on Bangladeshi officials found culpable of undermining the country's democratic election process.
The UN and other international organisations have also expressed alarm over human rights abuses and the stifling of dissent.
But Ms Hasina is aware that as long as India backs her, any threat of major sanctions by the West can be countered.Developed countries are also aware that any withdrawal of concessions to Bangladesh's garment industry would hit millions of workers, most of whom are women.
Ms Hasina first became the country's prime minister in 1996. She was re-elected in 2009 and has stayed in power since, making her the longest-serving leader in Bangladesh's history.
By the end of her term as prime minister, she will be 81. Who will succeed her is a big question for many in Bangladesh, including supporters of the Awami League.
As some analysts say, "the election result was clear, but the future looks uncertain".