Despite the coronavirus pandemic, total global military expenditure rose to nearly two trillion dollars last year.
According to data published on Monday by the Stockholm International Peace Research Institute, spending totalled $US1,981 billion ($A2.6 trillion), marking an increase of 2.6 per cent in real terms from 2019.
The five biggest spenders in 2020 were the United States, China, India, Russia and Britain.
Together they accounted for 62 per cent of global military expenditure.
Meanwhile, military spending by China grew for the 26th consecutive year.
"We can say with some certainty that the pandemic did not have a significant impact on global military spending in 2020," said Diego Lopes da Silva, a researcher with the SIPRI Arms and Military Expenditure Programme.
"It remains to be seen whether countries will maintain this level of military spending through a second year of the pandemic."
Despite a global defence spending rise, some countries explicitly re-allocated part of their planned military budget to pandemic response efforts, such as Chile and South Korea.
Others, including Brazil and Russia, spent considerably less than their initial military budgets for 2020, the institute said.
The US is the leader in defence spending, according to SIPRI.
In 2020, US military expenditure reached an estimated $US778 billion - a 4.4 per cent increase over 2019.
The US accounted for 39 per cent of total military expenditure in 2020.
This was the third consecutive year of growth in US spending, following seven years of reductions.