According to state media and local groups, 26 of those sentenced are currently detained, while 39 were convicted in absentia.
Military tribunals handed down the death sentences in areas of Yangon where the junta declared martial law in March.
In imposing martial law, the junta transferred all executive and judicial power to the head of the relevant regional military command and instituted the death penalty as a possible sentence for 23 crimes.
"The Myanmar junta has added to its mass shootings of protesters on the streets by having military tribunals hand down several dozen death sentences after egregiously unfair trials," said Shayna Bauchner, Asia researcher at Human Rights Watch, in a press release on Wednesday.
"Apparently aimed to chill the anti-coup protest movement, these death sentences should serve as a stark warning to foreign governments that urgent action is needed to show the junta that there will be a reckoning for its crimes," bauchner added.
Since February, the junta and security forces have responded with increasing violence and repression to the nationwide anti-coup movement.
State security forces have killed over 900 people and detained an estimated 5,300 activists, journalists, civil servants, and politicians.
Myanmar has not carried out judicial executions of prisoners since 1988, although Myanmar law still retains the death penalty, and courts have continued to sentence people to death.
"These bogus military tribunals are handing down unfair and unappealable death sentences under direction from a commander sanctioned by the European Union, United States, and others for committing the worst crimes under international law," Bauchner said.
"The United Nations, EU, US, and other governments should be demanding the release of all those wrongfully imprisoned and ramping up pressure so the junta knows that what they do – even behind prison doors – is being watched," Bauchner concluded.