The Southeast Asian nation is one of a handful of countries around the world that limits voting to those aged over 21, and the change still has to be debated and passed in the country's senate before it can become law.
The overhaul was championed by the government of Prime Minister Mahathir Mohamad -- who at 94 is the world's oldest leader -- about a year after it came to power by defeating a long-ruling, corruption-plagued coalition.
Speaking in the lower house of parliament before MPs voted on the law, Mahathir argued that young people in Malaysia were more politically aware than in the past.
"This move is so that they be given the chance, space and voice to... design the country's democracy through elections," he told lawmakers.
The reforms will also allow 18-year-olds to stand for election.
In addition, the amendments introduced automatic voter registration, with citizens eligible to cast their ballots as soon as they turn 18. Previously, people had to apply to get their names on the electoral roll.
Mahathir said that as many as 7.8 million people would be added to the electoral roll by the year 2023 through the move, bringing the country's total number of voters to 22.7 million.
Nearly 12.3 million people voted in the 2018 elections, from a total electorate of 14.9 million people.
Malaysia's population is around 32 million people.
After several hours of debate, 211 MPs voted in favour of amending Malaysia's federal constitution, allowing the changes to be introduced. No objections were recorded.
Two-thirds of the lower house's lawmakers needed to back constitutional changes in order for them to pass. The amendments will still have to be debated and passed in the country's senate before it can become law.
With the exception of Singapore -- which still maintains a 21-year voting age -- most people in Southeast Asia can vote when they turn 18. The voting age in Indonesia is 17.
The parliamentary vote represented a victory for Malaysia's four-party ruling coalition, the Alliance of Hope, which has faced a series of setbacks, including losing several local elections.
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