Suu Kyi, 80, was serving a 27-year sentence for a litany of offences her allies said were politically motivated to keep her at bay, ranging from incitement and corruption to election fraud and violating a state secrets law.
The sentence had been cut by one-sixth, but it remains unclear whether the Nobel Peace Prize winner would be allowed to serve the rest of her sentence under house arrest, the lawyer said.
The wildly popular Suu Kyi, who had dismissed the charges against her as "absurd", has not been seen in public since the end of her marathon trials, and her whereabouts have been unknown.
Earlier, state media reported that President Min Aung Hlaing approved an amnesty for 4335 prisoners, the third such move in the past six months.
Amnesties typically take place in Myanmar each year to mark Independence Day in January and New Year in April.
Among the prisoners freed was Win Myint, who served as president from 2018 until the 2021 military coup.
Win Myint, an ally of Suu Kyi, was "granted a pardon and the reduction of his remaining sentences under specified conditions", state broadcaster MRTV said.
A spokesperson for the military-backed government did not immediately respond to a request for comment.
The 2021 coup against Win Myint and Suu Kyi's democratically elected government was led by Min Aung Hlaing.
It plunged the Southeast Asian country into a nationwide civil war that continues to rage.
Min Aung Hlaing was elected president on April 3 following polls in December and January during which the opposition was stifled and largely absent.
Critics and Western governments dismissed the vote as a sham designed to entrench military rule behind a democratic facade.
