A Dhaka court handed down death sentences to six who raided the private bank on the outskirts of the capital, using grenades, guns and machetes.
Prosecution lawyers and police said the convicts belonged to outlawed Jamaatul Mujaheedin Bangladesh (JMB) and Ansarullah Bangla Team (ABT).
"They will be hanged until death," pronounced Dhaka's District and Sessions Judge S M Kuddus Zaman.
The court also sentenced three other militants from the groups to prison terms ranging from three years to life. Two other suspects were acquitted.
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"All of them were originally operatives of JMB but some of them later joined the newer outfit of ABT," a police officer familiar with the investigation earlier told newsmen.
Seven persons, including the bank's manager and an entrepreneur, were killed during the April 21, 2015 robbery at the Ashulia Industrial zone.
Police and bank officials earlier had called the heist "unusual and unprecedented" with an investigator saying "it was not aimed at robbery but something different...To kill people to cause panic (and) we don't think it was done for money alone".
In 2007, Bangladesh hanged six JMB's kingpins, including its founder Shaikh Abdur Rahman for murdering two lower court judges.
Bangladesh in recent months witnessed a wave of murders of liberal and secular activists, writers and minorities by suspected Islamist militants.
The Islamic State reportedly claimed responsibilities of most of the murders but Bangladeshi authorities rejected the claims.