Prof Yunus' supporters say the case is politically motivated.
The acclaimed economist and three colleagues from Grameen Telecom - one of the firms he founded - were found guilty of failing to create a welfare fund for their workers.
All four deny any wrongdoing and have been granted bail pending appeals.
"I call for the Bangladeshi people to speak in one voice against injustice and in favour of democracy and human rights for each and every one of our citizens."
The 83-year-old Yunus, known internationally as the "banker to the poor", is credited with establishing a pioneering system of micro-finance loans helping to lift millions out of poverty.
Prof Yunus and his Grameen Bank were jointly awarded the Nobel Peace Prize for their pioneering work in 2006.